From 84d55b276b4ea6f7f3860f7dc699e6ffc8c77995 Mon Sep 17 00:00:00 2001
From: mhucka <mhucka@google.com>
Date: Thu, 9 Jul 2026 02:06:56 +0000
Subject: [PATCH 01/42] Move conftest.py to the top level

Pytest seems to read the conf file at a different time during
execution if it is located at the top of the repo versus in a
subdirectory. Moving it the top makes things work more predictably.
---
 src/openfermion/conftest.py => conftest.py | 5 +++++
 1 file changed, 5 insertions(+)
 rename src/openfermion/conftest.py => conftest.py (82%)

diff --git a/src/openfermion/conftest.py b/conftest.py
similarity index 82%
rename from src/openfermion/conftest.py
rename to conftest.py
index 104edd1a1..72802c213 100644
--- a/src/openfermion/conftest.py
+++ b/conftest.py
@@ -12,11 +12,16 @@
 
 import os
 import random
+import sys
 from typing import Any
 
 import numpy as np
 import pytest
 
+# Ensure src/ is in sys.path so that the OpenFermion utils module can be
+# imported at Pytest startup time.
+sys.path.insert(0, os.path.abspath(os.path.join(os.path.dirname(__file__), "src")))
+
 
 def pytest_configure(config: Any) -> None:
     # Set seeds for collection-time parameterization.

From 021f05c11d6d6674659b6f7276e855f2340e1a5f Mon Sep 17 00:00:00 2001
From: mhucka <mhucka@google.com>
Date: Thu, 9 Jul 2026 02:07:52 +0000
Subject: [PATCH 02/42] Add pytest fixture to set threadpool limits

---
 conftest.py | 29 +++++++++++++++++++++++++++++
 1 file changed, 29 insertions(+)

diff --git a/conftest.py b/conftest.py
index 72802c213..037f05264 100644
--- a/conftest.py
+++ b/conftest.py
@@ -36,3 +36,32 @@ def set_random_seed() -> None:
     """Set a fixed random seed when testing."""
     random.seed(0)
     np.random.seed(0)
+
+
+@pytest.fixture(autouse=True, scope="session")
+def set_threadpool_limits():
+    """Limit number of threads to prevent oversubscription with pytest-xdist.
+
+    This only has an effect if the Python threadpoolctl package is installed,
+    and it only influences parallellism in some numerical libraries used in
+    packages such as NumPy.
+    """
+    try:
+        import threadpoolctl  # type: ignore
+    except ImportError:
+        yield
+        return
+
+    if "PYTEST_XDIST_WORKER_COUNT" in os.environ:
+        from openfermion.utils import get_available_cpu_count
+
+        try:
+            n_workers = max(1, int(os.environ["PYTEST_XDIST_WORKER_COUNT"]))
+        except ValueError:
+            n_workers = 1
+        max_threads_per_worker = max(1, get_available_cpu_count() // n_workers)
+        # Limit native library thread pools for this worker.
+        with threadpoolctl.threadpool_limits(limits=max_threads_per_worker):
+            yield
+    else:
+        yield

From ca386539739bfd819ea98800fcbff7a964fb1399 Mon Sep 17 00:00:00 2001
From: mhucka <mhucka@google.com>
Date: Thu, 9 Jul 2026 02:41:46 +0000
Subject: [PATCH 03/42] Count available CPU resources more carefully

---
 .../linalg/linear_qubit_operator.py           |  4 +--
 .../linalg/linear_qubit_operator_test.py      |  8 ++---
 .../thc/utils/thc_factorization.py            |  3 +-
 .../thc/utils/thc_objectives.py               |  3 +-
 src/openfermion/utils/__init__.py             |  1 +
 src/openfermion/utils/operator_utils.py       | 30 +++++++++++++++++++
 6 files changed, 41 insertions(+), 8 deletions(-)

diff --git a/src/openfermion/linalg/linear_qubit_operator.py b/src/openfermion/linalg/linear_qubit_operator.py
index 5a62b87bc..2262da938 100644
--- a/src/openfermion/linalg/linear_qubit_operator.py
+++ b/src/openfermion/linalg/linear_qubit_operator.py
@@ -20,7 +20,7 @@
 import scipy.sparse
 import scipy.sparse.linalg
 
-from openfermion.utils.operator_utils import count_qubits
+from openfermion.utils.operator_utils import count_qubits, get_available_cpu_count
 
 
 class LinearQubitOperatorOptions:
@@ -35,7 +35,7 @@ def __init__(self, processes=10, pool=None):
         if processes <= 0:
             raise ValueError('Invalid number of processors specified {} <= 0'.format(processes))
 
-        self.processes = min(processes, multiprocessing.cpu_count())
+        self.processes = min(processes, get_available_cpu_count())
         self.pool = pool
 
     def get_processes(self, num):
diff --git a/src/openfermion/linalg/linear_qubit_operator_test.py b/src/openfermion/linalg/linear_qubit_operator_test.py
index ee3e872c6..918bbf7bc 100644
--- a/src/openfermion/linalg/linear_qubit_operator_test.py
+++ b/src/openfermion/linalg/linear_qubit_operator_test.py
@@ -11,7 +11,6 @@
 #   limitations under the License.
 """Tests for linear_qubit_operator.py."""
 
-import multiprocessing
 import unittest
 
 import numpy
@@ -26,6 +25,7 @@
     generate_linear_qubit_operator,
 )
 from openfermion.linalg.sparse_tools import qubit_operator_sparse
+from openfermion.utils import get_available_cpu_count
 
 
 class LinearQubitOperatorOptionsTest(unittest.TestCase):
@@ -33,7 +33,7 @@ class LinearQubitOperatorOptionsTest(unittest.TestCase):
 
     def setUp(self):
         """LinearQubitOperatorOptions test set up."""
-        self.processes = multiprocessing.cpu_count()
+        self.processes = get_available_cpu_count()
         self.options = LinearQubitOperatorOptions(self.processes)
 
     def test_init(self):
@@ -214,13 +214,13 @@ def test_init(self):
         self.assertEqual(self.linear_operator.n_qubits, self.n_qubits)
         self.assertIsNone(self.linear_operator.options.pool)
 
-        cpu_count = multiprocessing.cpu_count()
+        cpu_count = get_available_cpu_count()
         default_processes = min(cpu_count, 10)
         self.assertEqual(self.linear_operator.options.processes, default_processes)
 
         # Generated variables.
         self.assertEqual(
-            len(self.linear_operator.qubit_operator_groups), min(multiprocessing.cpu_count(), 3)
+            len(self.linear_operator.qubit_operator_groups), min(get_available_cpu_count(), 3)
         )
         self.assertEqual(
             QubitOperator.accumulate(self.linear_operator.qubit_operator_groups),
diff --git a/src/openfermion/resource_estimates/thc/utils/thc_factorization.py b/src/openfermion/resource_estimates/thc/utils/thc_factorization.py
index 5b283df9e..49ce27404 100644
--- a/src/openfermion/resource_estimates/thc/utils/thc_factorization.py
+++ b/src/openfermion/resource_estimates/thc/utils/thc_factorization.py
@@ -14,6 +14,7 @@
 
 import jax.numpy as jnp
 from jax import jit, grad
+from openfermion.utils import get_available_cpu_count
 from .adagrad import adagrad
 from .thc_objectives import (
     thc_objective,
@@ -25,7 +26,7 @@
 
 # set mkl thread count for numpy einsum/tensordot calls
 # leave one CPU un used  so we can still access this computer
-os.environ["MKL_NUM_THREADS"] = str(max((os.cpu_count() or 1) - 1, 1))
+os.environ["MKL_NUM_THREADS"] = str(max(get_available_cpu_count() - 1, 1))
 
 
 class CallBackStore:
diff --git a/src/openfermion/resource_estimates/thc/utils/thc_objectives.py b/src/openfermion/resource_estimates/thc/utils/thc_objectives.py
index 5dc2f0292..b07ac9d03 100644
--- a/src/openfermion/resource_estimates/thc/utils/thc_objectives.py
+++ b/src/openfermion/resource_estimates/thc/utils/thc_objectives.py
@@ -15,11 +15,12 @@
 import numpy.random
 import numpy.linalg
 from scipy.optimize import minimize
+from openfermion.utils import get_available_cpu_count
 from .adagrad import adagrad
 
 # set mkl thread count for numpy einsum/tensordot calls
 # leave one CPU un used  so we can still access this computer
-os.environ["MKL_NUM_THREADS"] = str(max((os.cpu_count() or 1) - 1, 1))
+os.environ["MKL_NUM_THREADS"] = str(max(get_available_cpu_count() - 1, 1))
 
 
 def thc_objective_jax(xcur, norb, nthc, eri):
diff --git a/src/openfermion/utils/__init__.py b/src/openfermion/utils/__init__.py
index 5bec19680..0175bf9cf 100644
--- a/src/openfermion/utils/__init__.py
+++ b/src/openfermion/utils/__init__.py
@@ -32,6 +32,7 @@
 
 from .operator_utils import (
     count_qubits,
+    get_available_cpu_count,
     get_file_path,
     hermitian_conjugated,
     is_hermitian,
diff --git a/src/openfermion/utils/operator_utils.py b/src/openfermion/utils/operator_utils.py
index 8e55e35cd..f13ceaf38 100644
--- a/src/openfermion/utils/operator_utils.py
+++ b/src/openfermion/utils/operator_utils.py
@@ -44,6 +44,36 @@ class OperatorSpecificationError(Exception):
     pass
 
 
+def get_available_cpu_count() -> int:
+    """Returns the number of CPU cores available to the current process.
+
+    This function respects active CPU limits such as process affinity,
+    Docker container limits, and pytest-xdist worker distribution to
+    prevent oversubscription.
+    """
+    if hasattr(os, "process_cpu_count"):  # Python 3.13+
+        cpus = os.process_cpu_count() or 1
+    elif hasattr(os, "sched_getaffinity"):  # Unix/Linux
+        try:
+            cpus = len(os.sched_getaffinity(0))
+        except Exception:  # pylint: disable=broad-exception-caught
+            cpus = os.cpu_count() or 1
+    else:  # Fallback for older Python on Windows/macOS
+        cpus = os.cpu_count() or 1
+
+    # Divide by the number of active pytest-xdist workers.
+    if "PYTEST_XDIST_WORKER_COUNT" in os.environ:
+        try:
+            worker_count = int(os.environ["PYTEST_XDIST_WORKER_COUNT"])
+            if worker_count > 0:
+                # cpus = max(1, (cpus - 1) // worker_count)
+                cpus = max(1, cpus // worker_count)
+        except ValueError:
+            pass
+
+    return cpus
+
+
 def hermitian_conjugated(operator):
     """Return Hermitian conjugate of operator."""
     # Handle FermionOperator

From 0967fefe0ede3346e42ae52ab287372baac5ff12 Mon Sep 17 00:00:00 2001
From: mhucka <mhucka@google.com>
Date: Thu, 9 Jul 2026 02:46:04 +0000
Subject: [PATCH 04/42] Add unit tests for new cpu counting code

Thanks to Gemini 3.5 Flash for help.
---
 src/openfermion/utils/operator_utils_test.py | 122 +++++++++++++++++++
 1 file changed, 122 insertions(+)

diff --git a/src/openfermion/utils/operator_utils_test.py b/src/openfermion/utils/operator_utils_test.py
index 015cb0cfc..638556077 100644
--- a/src/openfermion/utils/operator_utils_test.py
+++ b/src/openfermion/utils/operator_utils_test.py
@@ -634,3 +634,125 @@ def test_file_load(self):
 
         filepath = get_file_path(self.filename, self.datadirname)
         self.assertEqual(filepath, self.datadirname + '/' + self.filename + '.data')
+
+
+class MockOS:
+    def __init__(
+        self, process_cpu_count_val=None, sched_getaffinity_val=None, cpu_count_val=4, environ=None
+    ):
+        if process_cpu_count_val is not None:
+            self.process_cpu_count = lambda: process_cpu_count_val
+        if sched_getaffinity_val is not None:
+            if isinstance(sched_getaffinity_val, Exception):
+
+                def raise_exc():
+                    raise sched_getaffinity_val
+
+                self.sched_getaffinity = lambda x: raise_exc()
+            else:
+                self.sched_getaffinity = lambda x: sched_getaffinity_val
+        self.cpu_count = lambda: cpu_count_val
+        self.environ = environ if environ is not None else {}
+
+
+class GetAvailableCpuCountTest(unittest.TestCase):
+
+    def test_get_available_cpu_count_various_os(self):
+        from unittest.mock import patch
+        import openfermion.utils.operator_utils as op_utils
+        from openfermion.utils.operator_utils import get_available_cpu_count
+
+        # Test Case 1: Python 3.13+ (has process_cpu_count).
+        mock_os = MockOS(process_cpu_count_val=8)
+        with patch.object(op_utils, "os", mock_os):
+            self.assertEqual(get_available_cpu_count(), 8)
+
+        # Test Case 1b: Python 3.13+ returns 0/None -> fallback to 1.
+        mock_os = MockOS(process_cpu_count_val=0)
+        with patch.object(op_utils, "os", mock_os):
+            self.assertEqual(get_available_cpu_count(), 1)
+
+        # Test Case 2: Linux/Unix (no process_cpu_count, has sched_getaffinity).
+        mock_os = MockOS(sched_getaffinity_val=[1, 2, 3, 4])
+        with patch.object(op_utils, "os", mock_os):
+            self.assertEqual(get_available_cpu_count(), 4)
+
+        # Test Case 3: Linux/Unix but sched_getaffinity raises exception.
+        mock_os = MockOS(sched_getaffinity_val=ValueError("error"), cpu_count_val=4)
+        with patch.object(op_utils, "os", mock_os):
+            self.assertEqual(get_available_cpu_count(), 4)
+
+        # Test Case 4: Windows/macOS/Older Python Fallback.
+        mock_os = MockOS(cpu_count_val=6)
+        with patch.object(op_utils, "os", mock_os):
+            self.assertEqual(get_available_cpu_count(), 6)
+
+        # Test Case 4b: Fallback when cpu_count returns None/0.
+        mock_os = MockOS(cpu_count_val=0)
+        with patch.object(op_utils, "os", mock_os):
+            self.assertEqual(get_available_cpu_count(), 1)
+
+        # Test Case 5: pytest-xdist active with valid worker count.
+        mock_os = MockOS(cpu_count_val=8, environ={"PYTEST_XDIST_WORKER_COUNT": "4"})
+        with patch.object(op_utils, "os", mock_os):
+            self.assertEqual(get_available_cpu_count(), 2)
+
+        # Test Case 6: pytest-xdist with invalid worker count.
+        mock_os = MockOS(cpu_count_val=8, environ={"PYTEST_XDIST_WORKER_COUNT": "abc"})
+        with patch.object(op_utils, "os", mock_os):
+            self.assertEqual(get_available_cpu_count(), 8)
+
+
+class SetThreadpoolLimitsTest(unittest.TestCase):
+
+    def test_set_threadpool_limits_fixture(self):
+        import conftest
+        import sys
+        from unittest.mock import patch, MagicMock
+
+        # Test Case 1: threadpoolctl is not installed.
+        with patch.dict(sys.modules, {"threadpoolctl": None}):
+            gen = conftest.set_threadpool_limits.__wrapped__()
+            val = next(gen)
+            self.assertIsNone(val)
+            with self.assertRaises(StopIteration):
+                next(gen)
+
+        # Mock threadpoolctl and os.environ for the remaining cases.
+        mock_threadpoolctl = MagicMock()
+        mock_threadpoolctl.threadpool_limits.return_value = MagicMock()
+
+        with patch.dict(sys.modules, {"threadpoolctl": mock_threadpoolctl}):
+            # Test Case 2: PYTEST_XDIST_WORKER_COUNT is in os.environ.
+            with patch.dict(os.environ, {"PYTEST_XDIST_WORKER_COUNT": "4"}):
+                with patch("openfermion.utils.get_available_cpu_count", return_value=8):
+                    gen = conftest.set_threadpool_limits.__wrapped__()
+                    val = next(gen)
+                    self.assertIsNone(val)
+                    mock_threadpoolctl.threadpool_limits.assert_called_once()
+                    mock_threadpoolctl.threadpool_limits.assert_called_with(limits=2)
+                    with self.assertRaises(StopIteration):
+                        next(gen)
+                    mock_threadpoolctl.reset_mock()
+
+            # Test Case 3: PYTEST_XDIST_WORKER_COUNT is in os.environ but invalid.
+            with patch.dict(os.environ, {"PYTEST_XDIST_WORKER_COUNT": "abc"}):
+                with patch("openfermion.utils.get_available_cpu_count", return_value=8):
+                    gen = conftest.set_threadpool_limits.__wrapped__()
+
+                    val = next(gen)
+                    self.assertIsNone(val)
+                    mock_threadpoolctl.threadpool_limits.assert_called_once()
+                    mock_threadpoolctl.threadpool_limits.assert_called_with(limits=8)
+                    with self.assertRaises(StopIteration):
+                        next(gen)
+                    mock_threadpoolctl.reset_mock()
+
+            # Test Case 4: PYTEST_XDIST_WORKER_COUNT is not in os.environ.
+            with patch.dict(os.environ, {}, clear=True):
+                gen = conftest.set_threadpool_limits.__wrapped__()
+                val = next(gen)
+                self.assertIsNone(val)
+                mock_threadpoolctl.threadpool_limits.assert_not_called()
+                with self.assertRaises(StopIteration):
+                    next(gen)

From 632ec444ae1532fd13420d7ee4c892bb044bea8c Mon Sep 17 00:00:00 2001
From: mhucka <mhucka@google.com>
Date: Thu, 9 Jul 2026 03:07:37 +0000
Subject: [PATCH 05/42] Make type ignore comments more specific

---
 conftest.py                                              | 2 +-
 src/openfermion/circuits/primitives/state_preparation.py | 6 +++---
 2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/conftest.py b/conftest.py
index 037f05264..483005827 100644
--- a/conftest.py
+++ b/conftest.py
@@ -47,7 +47,7 @@ def set_threadpool_limits():
     packages such as NumPy.
     """
     try:
-        import threadpoolctl  # type: ignore
+        import threadpoolctl  # type: ignore[import-untyped]
     except ImportError:
         yield
         return
diff --git a/src/openfermion/circuits/primitives/state_preparation.py b/src/openfermion/circuits/primitives/state_preparation.py
index 220a406f9..4a27e7ee9 100644
--- a/src/openfermion/circuits/primitives/state_preparation.py
+++ b/src/openfermion/circuits/primitives/state_preparation.py
@@ -95,7 +95,7 @@ def _generic_gaussian_circuit(
     if isinstance(initial_state, int):
         initially_occupied_orbitals = _occupied_orbitals(initial_state, n_qubits)
     else:
-        initially_occupied_orbitals = initial_state  # type: ignore
+        initially_occupied_orbitals = initial_state  # type: ignore[assignment]
 
     # Flip bits so that the correct starting orbitals are occupied
     yield (
@@ -118,7 +118,7 @@ def _spin_symmetric_gaussian_circuit(
     if isinstance(initial_state, int):
         initially_occupied_orbitals = _occupied_orbitals(initial_state, n_qubits)
     else:
-        initially_occupied_orbitals = initial_state  # type: ignore
+        initially_occupied_orbitals = initial_state  # type: ignore[assignment]
 
     for spin_sector in range(2):
         circuit_description, start_orbitals = gaussian_state_preparation_circuit(
@@ -190,7 +190,7 @@ def prepare_slater_determinant(
     if isinstance(initial_state, int):
         initially_occupied_orbitals = _occupied_orbitals(initial_state, n_qubits)
     else:
-        initially_occupied_orbitals = initial_state  # type: ignore
+        initially_occupied_orbitals = initial_state  # type: ignore[assignment]
 
     # Flip bits so that the first n_occupied are 1 and the rest 0
     yield (

From af3d4d863fc7415e8eeeedded83a58e98f980d62 Mon Sep 17 00:00:00 2001
From: mhucka <mhucka@google.com>
Date: Thu, 9 Jul 2026 03:36:38 +0000
Subject: [PATCH 06/42] Ignore not found import

---
 conftest.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/conftest.py b/conftest.py
index 483005827..f99b92dd1 100644
--- a/conftest.py
+++ b/conftest.py
@@ -47,7 +47,7 @@ def set_threadpool_limits():
     packages such as NumPy.
     """
     try:
-        import threadpoolctl  # type: ignore[import-untyped]
+        import threadpoolctl  # type: ignore[import-untyped, import-not-found]
     except ImportError:
         yield
         return

From 98c417df263a9702916e00c432f84834e95c1747 Mon Sep 17 00:00:00 2001
From: Michael Hucka <mhucka@google.com>
Date: Wed, 8 Jul 2026 21:43:32 -0700
Subject: [PATCH 07/42] Update src/openfermion/utils/operator_utils_test.py

Co-authored-by: gemini-code-assist[bot] <176961590+gemini-code-assist[bot]@users.noreply.github.com>
---
 src/openfermion/utils/operator_utils_test.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/openfermion/utils/operator_utils_test.py b/src/openfermion/utils/operator_utils_test.py
index 638556077..8181492cd 100644
--- a/src/openfermion/utils/operator_utils_test.py
+++ b/src/openfermion/utils/operator_utils_test.py
@@ -725,7 +725,7 @@ def test_set_threadpool_limits_fixture(self):
         with patch.dict(sys.modules, {"threadpoolctl": mock_threadpoolctl}):
             # Test Case 2: PYTEST_XDIST_WORKER_COUNT is in os.environ.
             with patch.dict(os.environ, {"PYTEST_XDIST_WORKER_COUNT": "4"}):
-                with patch("openfermion.utils.get_available_cpu_count", return_value=8):
+                with patch("openfermion.utils.get_available_cpu_count", return_value=2):
                     gen = conftest.set_threadpool_limits.__wrapped__()
                     val = next(gen)
                     self.assertIsNone(val)

From 259e36e4622db1b4242e1f8df4f050d787b135b0 Mon Sep 17 00:00:00 2001
From: mhucka <mhucka@google.com>
Date: Thu, 9 Jul 2026 04:47:24 +0000
Subject: [PATCH 08/42] Fix error in worker calculation

As pointed out by Gemini Code Assist, the cpu count was already divided
by the xdist worker count.
---
 conftest.py | 8 +-------
 1 file changed, 1 insertion(+), 7 deletions(-)

diff --git a/conftest.py b/conftest.py
index f99b92dd1..e5c8c703e 100644
--- a/conftest.py
+++ b/conftest.py
@@ -54,14 +54,8 @@ def set_threadpool_limits():
 
     if "PYTEST_XDIST_WORKER_COUNT" in os.environ:
         from openfermion.utils import get_available_cpu_count
-
-        try:
-            n_workers = max(1, int(os.environ["PYTEST_XDIST_WORKER_COUNT"]))
-        except ValueError:
-            n_workers = 1
-        max_threads_per_worker = max(1, get_available_cpu_count() // n_workers)
         # Limit native library thread pools for this worker.
-        with threadpoolctl.threadpool_limits(limits=max_threads_per_worker):
+        with threadpoolctl.threadpool_limits(limits=get_available_cpu_count()):
             yield
     else:
         yield

From ac2cdf882f2e4c5c737d8d398309fd3c37e2c6c8 Mon Sep 17 00:00:00 2001
From: mhucka <mhucka@google.com>
Date: Thu, 9 Jul 2026 04:47:50 +0000
Subject: [PATCH 09/42] Format

---
 conftest.py | 1 +
 1 file changed, 1 insertion(+)

diff --git a/conftest.py b/conftest.py
index e5c8c703e..34df6b5c7 100644
--- a/conftest.py
+++ b/conftest.py
@@ -54,6 +54,7 @@ def set_threadpool_limits():
 
     if "PYTEST_XDIST_WORKER_COUNT" in os.environ:
         from openfermion.utils import get_available_cpu_count
+
         # Limit native library thread pools for this worker.
         with threadpoolctl.threadpool_limits(limits=get_available_cpu_count()):
             yield

From f5b7795e023b2b5d3cb662af3a5c27956bf73a74 Mon Sep 17 00:00:00 2001
From: mhucka <mhucka@google.com>
Date: Thu, 9 Jul 2026 17:04:46 +0000
Subject: [PATCH 10/42] Move `get_available_cpu_count()` to config.py

The fact that operator_utils.py imported numpy, scipy, and other
libraries made it impossible to import `get_available_cpu_count()`
alone. This in turn prevented using it to set things before NumPy and
other libraries were loaded.
---
 conftest.py                                   |   2 +-
 src/openfermion/config.py                     |  30 ++++
 src/openfermion/config_test.py                | 140 ++++++++++++++++++
 .../linalg/linear_qubit_operator.py           |   3 +-
 .../linalg/linear_qubit_operator_test.py      |   2 +-
 src/openfermion/utils/__init__.py             |   1 -
 src/openfermion/utils/operator_utils.py       |  30 ----
 src/openfermion/utils/operator_utils_test.py  | 122 ---------------
 8 files changed, 174 insertions(+), 156 deletions(-)
 create mode 100644 src/openfermion/config_test.py

diff --git a/conftest.py b/conftest.py
index 34df6b5c7..6dafd7443 100644
--- a/conftest.py
+++ b/conftest.py
@@ -53,7 +53,7 @@ def set_threadpool_limits():
         return
 
     if "PYTEST_XDIST_WORKER_COUNT" in os.environ:
-        from openfermion.utils import get_available_cpu_count
+        from openfermion.config import get_available_cpu_count
 
         # Limit native library thread pools for this worker.
         with threadpoolctl.threadpool_limits(limits=get_available_cpu_count()):
diff --git a/src/openfermion/config.py b/src/openfermion/config.py
index ec9600cf9..ab22adeb2 100644
--- a/src/openfermion/config.py
+++ b/src/openfermion/config.py
@@ -24,3 +24,33 @@
 # Molecular data directory.
 THIS_DIRECTORY = os.path.dirname(os.path.realpath(__file__))
 DATA_DIRECTORY = os.path.realpath(os.path.join(THIS_DIRECTORY, 'testing/data'))
+
+
+def get_available_cpu_count() -> int:
+    """Returns the number of CPU cores available to the current process.
+
+    This function respects active CPU limits such as process affinity,
+    Docker container limits, and pytest-xdist worker distribution to
+    prevent oversubscription.
+    """
+    if hasattr(os, "process_cpu_count"):  # Python 3.13+
+        cpus = os.process_cpu_count() or 1
+    elif hasattr(os, "sched_getaffinity"):  # Unix/Linux
+        try:
+            cpus = len(os.sched_getaffinity(0))
+        except Exception:  # pylint: disable=broad-exception-caught
+            cpus = os.cpu_count() or 1
+    else:  # Fallback for older Python on Windows/macOS
+        cpus = os.cpu_count() or 1
+
+    # Divide by the number of active pytest-xdist workers.
+    if "PYTEST_XDIST_WORKER_COUNT" in os.environ:
+        try:
+            worker_count = int(os.environ["PYTEST_XDIST_WORKER_COUNT"])
+            if worker_count > 0:
+                # cpus = max(1, (cpus - 1) // worker_count)
+                cpus = max(1, cpus // worker_count)
+        except ValueError:
+            pass
+
+    return cpus
diff --git a/src/openfermion/config_test.py b/src/openfermion/config_test.py
new file mode 100644
index 000000000..966b17004
--- /dev/null
+++ b/src/openfermion/config_test.py
@@ -0,0 +1,140 @@
+# Copyright 2026 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""Tests for config.py."""
+
+import os
+import unittest
+
+
+class MockOS:
+    def __init__(
+        self, process_cpu_count_val=None, sched_getaffinity_val=None, cpu_count_val=4, environ=None
+    ):
+        if process_cpu_count_val is not None:
+            self.process_cpu_count = lambda: process_cpu_count_val
+        if sched_getaffinity_val is not None:
+            if isinstance(sched_getaffinity_val, Exception):
+
+                def raise_exc():
+                    raise sched_getaffinity_val
+
+                self.sched_getaffinity = lambda x: raise_exc()
+            else:
+                self.sched_getaffinity = lambda x: sched_getaffinity_val
+        self.cpu_count = lambda: cpu_count_val
+        self.environ = environ if environ is not None else {}
+
+
+class GetAvailableCpuCountTest(unittest.TestCase):
+
+    def test_get_available_cpu_count_various_os(self):
+        from unittest.mock import patch
+        from openfermion.config import get_available_cpu_count
+        import openfermion.config as config
+
+        # Test Case 1: Python 3.13+ (has process_cpu_count).
+        mock_os = MockOS(process_cpu_count_val=8)
+        with patch.object(config, "os", mock_os):
+            self.assertEqual(get_available_cpu_count(), 8)
+
+        # Test Case 1b: Python 3.13+ returns 0/None -> fallback to 1.
+        mock_os = MockOS(process_cpu_count_val=0)
+        with patch.object(config, "os", mock_os):
+            self.assertEqual(get_available_cpu_count(), 1)
+
+        # Test Case 2: Linux/Unix (no process_cpu_count, has sched_getaffinity).
+        mock_os = MockOS(sched_getaffinity_val=[1, 2, 3, 4])
+        with patch.object(config, "os", mock_os):
+            self.assertEqual(get_available_cpu_count(), 4)
+
+        # Test Case 3: Linux/Unix but sched_getaffinity raises exception.
+        mock_os = MockOS(sched_getaffinity_val=ValueError("error"), cpu_count_val=4)
+        with patch.object(config, "os", mock_os):
+            self.assertEqual(get_available_cpu_count(), 4)
+
+        # Test Case 4: Windows/macOS/Older Python Fallback.
+        mock_os = MockOS(cpu_count_val=6)
+        with patch.object(config, "os", mock_os):
+            self.assertEqual(get_available_cpu_count(), 6)
+
+        # Test Case 4b: Fallback when cpu_count returns None/0.
+        mock_os = MockOS(cpu_count_val=0)
+        with patch.object(config, "os", mock_os):
+            self.assertEqual(get_available_cpu_count(), 1)
+
+        # Test Case 5: pytest-xdist active with valid worker count.
+        mock_os = MockOS(cpu_count_val=8, environ={"PYTEST_XDIST_WORKER_COUNT": "4"})
+        with patch.object(config, "os", mock_os):
+            self.assertEqual(get_available_cpu_count(), 2)
+
+        # Test Case 6: pytest-xdist with invalid worker count.
+        mock_os = MockOS(cpu_count_val=8, environ={"PYTEST_XDIST_WORKER_COUNT": "abc"})
+        with patch.object(config, "os", mock_os):
+            self.assertEqual(get_available_cpu_count(), 8)
+
+
+class SetThreadpoolLimitsTest(unittest.TestCase):
+
+    def test_set_threadpool_limits_fixture(self):
+        import conftest
+        import sys
+        from unittest.mock import patch, MagicMock
+
+        # Test Case 1: threadpoolctl is not installed.
+        with patch.dict(sys.modules, {"threadpoolctl": None}):
+            gen = conftest.set_threadpool_limits.__wrapped__()
+            val = next(gen)
+            self.assertIsNone(val)
+            with self.assertRaises(StopIteration):
+                next(gen)
+
+        # Mock threadpoolctl and os.environ for the remaining cases.
+        mock_threadpoolctl = MagicMock()
+        mock_threadpoolctl.threadpool_limits.return_value = MagicMock()
+
+        with patch.dict(sys.modules, {"threadpoolctl": mock_threadpoolctl}):
+            # Test Case 2: PYTEST_XDIST_WORKER_COUNT is in os.environ.
+            with patch.dict(os.environ, {"PYTEST_XDIST_WORKER_COUNT": "4"}):
+                with patch("openfermion.config.get_available_cpu_count", return_value=2):
+                    gen = conftest.set_threadpool_limits.__wrapped__()
+                    val = next(gen)
+                    self.assertIsNone(val)
+                    mock_threadpoolctl.threadpool_limits.assert_called_once()
+                    mock_threadpoolctl.threadpool_limits.assert_called_with(limits=2)
+                    with self.assertRaises(StopIteration):
+                        next(gen)
+                    mock_threadpoolctl.reset_mock()
+
+            # Test Case 3: PYTEST_XDIST_WORKER_COUNT is in os.environ but invalid.
+            with patch.dict(os.environ, {"PYTEST_XDIST_WORKER_COUNT": "abc"}):
+                with patch("openfermion.config.get_available_cpu_count", return_value=8):
+                    gen = conftest.set_threadpool_limits.__wrapped__()
+
+                    val = next(gen)
+                    self.assertIsNone(val)
+                    mock_threadpoolctl.threadpool_limits.assert_called_once()
+                    mock_threadpoolctl.threadpool_limits.assert_called_with(limits=8)
+                    with self.assertRaises(StopIteration):
+                        next(gen)
+                    mock_threadpoolctl.reset_mock()
+
+            # Test Case 4: PYTEST_XDIST_WORKER_COUNT is not in os.environ.
+            with patch.dict(os.environ, {}, clear=True):
+                gen = conftest.set_threadpool_limits.__wrapped__()
+                val = next(gen)
+                self.assertIsNone(val)
+                mock_threadpoolctl.threadpool_limits.assert_not_called()
+                with self.assertRaises(StopIteration):
+                    next(gen)
diff --git a/src/openfermion/linalg/linear_qubit_operator.py b/src/openfermion/linalg/linear_qubit_operator.py
index 2262da938..139878f35 100644
--- a/src/openfermion/linalg/linear_qubit_operator.py
+++ b/src/openfermion/linalg/linear_qubit_operator.py
@@ -20,7 +20,8 @@
 import scipy.sparse
 import scipy.sparse.linalg
 
-from openfermion.utils.operator_utils import count_qubits, get_available_cpu_count
+from openfermion.utils.operator_utils import count_qubits
+from openfermion.config import get_available_cpu_count
 
 
 class LinearQubitOperatorOptions:
diff --git a/src/openfermion/linalg/linear_qubit_operator_test.py b/src/openfermion/linalg/linear_qubit_operator_test.py
index 918bbf7bc..7b31113a9 100644
--- a/src/openfermion/linalg/linear_qubit_operator_test.py
+++ b/src/openfermion/linalg/linear_qubit_operator_test.py
@@ -25,7 +25,7 @@
     generate_linear_qubit_operator,
 )
 from openfermion.linalg.sparse_tools import qubit_operator_sparse
-from openfermion.utils import get_available_cpu_count
+from openfermion.config import get_available_cpu_count
 
 
 class LinearQubitOperatorOptionsTest(unittest.TestCase):
diff --git a/src/openfermion/utils/__init__.py b/src/openfermion/utils/__init__.py
index 0175bf9cf..5bec19680 100644
--- a/src/openfermion/utils/__init__.py
+++ b/src/openfermion/utils/__init__.py
@@ -32,7 +32,6 @@
 
 from .operator_utils import (
     count_qubits,
-    get_available_cpu_count,
     get_file_path,
     hermitian_conjugated,
     is_hermitian,
diff --git a/src/openfermion/utils/operator_utils.py b/src/openfermion/utils/operator_utils.py
index f13ceaf38..8e55e35cd 100644
--- a/src/openfermion/utils/operator_utils.py
+++ b/src/openfermion/utils/operator_utils.py
@@ -44,36 +44,6 @@ class OperatorSpecificationError(Exception):
     pass
 
 
-def get_available_cpu_count() -> int:
-    """Returns the number of CPU cores available to the current process.
-
-    This function respects active CPU limits such as process affinity,
-    Docker container limits, and pytest-xdist worker distribution to
-    prevent oversubscription.
-    """
-    if hasattr(os, "process_cpu_count"):  # Python 3.13+
-        cpus = os.process_cpu_count() or 1
-    elif hasattr(os, "sched_getaffinity"):  # Unix/Linux
-        try:
-            cpus = len(os.sched_getaffinity(0))
-        except Exception:  # pylint: disable=broad-exception-caught
-            cpus = os.cpu_count() or 1
-    else:  # Fallback for older Python on Windows/macOS
-        cpus = os.cpu_count() or 1
-
-    # Divide by the number of active pytest-xdist workers.
-    if "PYTEST_XDIST_WORKER_COUNT" in os.environ:
-        try:
-            worker_count = int(os.environ["PYTEST_XDIST_WORKER_COUNT"])
-            if worker_count > 0:
-                # cpus = max(1, (cpus - 1) // worker_count)
-                cpus = max(1, cpus // worker_count)
-        except ValueError:
-            pass
-
-    return cpus
-
-
 def hermitian_conjugated(operator):
     """Return Hermitian conjugate of operator."""
     # Handle FermionOperator
diff --git a/src/openfermion/utils/operator_utils_test.py b/src/openfermion/utils/operator_utils_test.py
index 8181492cd..015cb0cfc 100644
--- a/src/openfermion/utils/operator_utils_test.py
+++ b/src/openfermion/utils/operator_utils_test.py
@@ -634,125 +634,3 @@ def test_file_load(self):
 
         filepath = get_file_path(self.filename, self.datadirname)
         self.assertEqual(filepath, self.datadirname + '/' + self.filename + '.data')
-
-
-class MockOS:
-    def __init__(
-        self, process_cpu_count_val=None, sched_getaffinity_val=None, cpu_count_val=4, environ=None
-    ):
-        if process_cpu_count_val is not None:
-            self.process_cpu_count = lambda: process_cpu_count_val
-        if sched_getaffinity_val is not None:
-            if isinstance(sched_getaffinity_val, Exception):
-
-                def raise_exc():
-                    raise sched_getaffinity_val
-
-                self.sched_getaffinity = lambda x: raise_exc()
-            else:
-                self.sched_getaffinity = lambda x: sched_getaffinity_val
-        self.cpu_count = lambda: cpu_count_val
-        self.environ = environ if environ is not None else {}
-
-
-class GetAvailableCpuCountTest(unittest.TestCase):
-
-    def test_get_available_cpu_count_various_os(self):
-        from unittest.mock import patch
-        import openfermion.utils.operator_utils as op_utils
-        from openfermion.utils.operator_utils import get_available_cpu_count
-
-        # Test Case 1: Python 3.13+ (has process_cpu_count).
-        mock_os = MockOS(process_cpu_count_val=8)
-        with patch.object(op_utils, "os", mock_os):
-            self.assertEqual(get_available_cpu_count(), 8)
-
-        # Test Case 1b: Python 3.13+ returns 0/None -> fallback to 1.
-        mock_os = MockOS(process_cpu_count_val=0)
-        with patch.object(op_utils, "os", mock_os):
-            self.assertEqual(get_available_cpu_count(), 1)
-
-        # Test Case 2: Linux/Unix (no process_cpu_count, has sched_getaffinity).
-        mock_os = MockOS(sched_getaffinity_val=[1, 2, 3, 4])
-        with patch.object(op_utils, "os", mock_os):
-            self.assertEqual(get_available_cpu_count(), 4)
-
-        # Test Case 3: Linux/Unix but sched_getaffinity raises exception.
-        mock_os = MockOS(sched_getaffinity_val=ValueError("error"), cpu_count_val=4)
-        with patch.object(op_utils, "os", mock_os):
-            self.assertEqual(get_available_cpu_count(), 4)
-
-        # Test Case 4: Windows/macOS/Older Python Fallback.
-        mock_os = MockOS(cpu_count_val=6)
-        with patch.object(op_utils, "os", mock_os):
-            self.assertEqual(get_available_cpu_count(), 6)
-
-        # Test Case 4b: Fallback when cpu_count returns None/0.
-        mock_os = MockOS(cpu_count_val=0)
-        with patch.object(op_utils, "os", mock_os):
-            self.assertEqual(get_available_cpu_count(), 1)
-
-        # Test Case 5: pytest-xdist active with valid worker count.
-        mock_os = MockOS(cpu_count_val=8, environ={"PYTEST_XDIST_WORKER_COUNT": "4"})
-        with patch.object(op_utils, "os", mock_os):
-            self.assertEqual(get_available_cpu_count(), 2)
-
-        # Test Case 6: pytest-xdist with invalid worker count.
-        mock_os = MockOS(cpu_count_val=8, environ={"PYTEST_XDIST_WORKER_COUNT": "abc"})
-        with patch.object(op_utils, "os", mock_os):
-            self.assertEqual(get_available_cpu_count(), 8)
-
-
-class SetThreadpoolLimitsTest(unittest.TestCase):
-
-    def test_set_threadpool_limits_fixture(self):
-        import conftest
-        import sys
-        from unittest.mock import patch, MagicMock
-
-        # Test Case 1: threadpoolctl is not installed.
-        with patch.dict(sys.modules, {"threadpoolctl": None}):
-            gen = conftest.set_threadpool_limits.__wrapped__()
-            val = next(gen)
-            self.assertIsNone(val)
-            with self.assertRaises(StopIteration):
-                next(gen)
-
-        # Mock threadpoolctl and os.environ for the remaining cases.
-        mock_threadpoolctl = MagicMock()
-        mock_threadpoolctl.threadpool_limits.return_value = MagicMock()
-
-        with patch.dict(sys.modules, {"threadpoolctl": mock_threadpoolctl}):
-            # Test Case 2: PYTEST_XDIST_WORKER_COUNT is in os.environ.
-            with patch.dict(os.environ, {"PYTEST_XDIST_WORKER_COUNT": "4"}):
-                with patch("openfermion.utils.get_available_cpu_count", return_value=2):
-                    gen = conftest.set_threadpool_limits.__wrapped__()
-                    val = next(gen)
-                    self.assertIsNone(val)
-                    mock_threadpoolctl.threadpool_limits.assert_called_once()
-                    mock_threadpoolctl.threadpool_limits.assert_called_with(limits=2)
-                    with self.assertRaises(StopIteration):
-                        next(gen)
-                    mock_threadpoolctl.reset_mock()
-
-            # Test Case 3: PYTEST_XDIST_WORKER_COUNT is in os.environ but invalid.
-            with patch.dict(os.environ, {"PYTEST_XDIST_WORKER_COUNT": "abc"}):
-                with patch("openfermion.utils.get_available_cpu_count", return_value=8):
-                    gen = conftest.set_threadpool_limits.__wrapped__()
-
-                    val = next(gen)
-                    self.assertIsNone(val)
-                    mock_threadpoolctl.threadpool_limits.assert_called_once()
-                    mock_threadpoolctl.threadpool_limits.assert_called_with(limits=8)
-                    with self.assertRaises(StopIteration):
-                        next(gen)
-                    mock_threadpoolctl.reset_mock()
-
-            # Test Case 4: PYTEST_XDIST_WORKER_COUNT is not in os.environ.
-            with patch.dict(os.environ, {}, clear=True):
-                gen = conftest.set_threadpool_limits.__wrapped__()
-                val = next(gen)
-                self.assertIsNone(val)
-                mock_threadpoolctl.threadpool_limits.assert_not_called()
-                with self.assertRaises(StopIteration):
-                    next(gen)

From 0031a24e9805558a5aa147069d01e2a01c2e3c2e Mon Sep 17 00:00:00 2001
From: mhucka <mhucka@google.com>
Date: Thu, 9 Jul 2026 17:05:09 +0000
Subject: [PATCH 11/42] Set MKL_NUM_THREADS before loading numpy and others

---
 .../thc/utils/thc_factorization.py                | 15 ++++++++++-----
 .../thc/utils/thc_objectives.py                   | 15 ++++++++++-----
 2 files changed, 20 insertions(+), 10 deletions(-)

diff --git a/src/openfermion/resource_estimates/thc/utils/thc_factorization.py b/src/openfermion/resource_estimates/thc/utils/thc_factorization.py
index 49ce27404..899365b3e 100644
--- a/src/openfermion/resource_estimates/thc/utils/thc_factorization.py
+++ b/src/openfermion/resource_estimates/thc/utils/thc_factorization.py
@@ -1,6 +1,15 @@
 # coverage:ignore
 # pylint: disable=wrong-import-position
 import os
+
+from openfermion.config import get_available_cpu_count
+
+# Set Intel MKL thread count for NumPy einsum/tensordot calls.
+# Needs to be set before other libraries are loaded.
+# Reduce count by 1 to lessen impact on host system.
+os.environ["MKL_NUM_THREADS"] = str(max(get_available_cpu_count() - 1, 1))
+
+
 from uuid import uuid4
 import h5py
 import numpy
@@ -14,7 +23,7 @@
 
 import jax.numpy as jnp
 from jax import jit, grad
-from openfermion.utils import get_available_cpu_count
+
 from .adagrad import adagrad
 from .thc_objectives import (
     thc_objective,
@@ -24,10 +33,6 @@
     thc_objective_regularized,
 )
 
-# set mkl thread count for numpy einsum/tensordot calls
-# leave one CPU un used  so we can still access this computer
-os.environ["MKL_NUM_THREADS"] = str(max(get_available_cpu_count() - 1, 1))
-
 
 class CallBackStore:
     def __init__(self, chkpoint_file, freqency=500):
diff --git a/src/openfermion/resource_estimates/thc/utils/thc_objectives.py b/src/openfermion/resource_estimates/thc/utils/thc_objectives.py
index b07ac9d03..d3488932d 100644
--- a/src/openfermion/resource_estimates/thc/utils/thc_objectives.py
+++ b/src/openfermion/resource_estimates/thc/utils/thc_objectives.py
@@ -1,6 +1,15 @@
 # coverage:ignore
 # pylint: disable=wrong-import-position
 import os
+
+from openfermion.config import get_available_cpu_count
+
+# Set Intel MKL thread count for NumPy einsum/tensordot calls.
+# Needs to be set before other libraries are loaded.
+# Reduce count by 1 to lessen impact on host system.
+os.environ["MKL_NUM_THREADS"] = str(max(get_available_cpu_count() - 1, 1))
+
+
 from uuid import uuid4
 import scipy.optimize
 
@@ -15,13 +24,9 @@
 import numpy.random
 import numpy.linalg
 from scipy.optimize import minimize
-from openfermion.utils import get_available_cpu_count
+from openfermion.config import get_available_cpu_count
 from .adagrad import adagrad
 
-# set mkl thread count for numpy einsum/tensordot calls
-# leave one CPU un used  so we can still access this computer
-os.environ["MKL_NUM_THREADS"] = str(max(get_available_cpu_count() - 1, 1))
-
 
 def thc_objective_jax(xcur, norb, nthc, eri):
     """

From 173c1ecefba39a10c12fc5da7d63998dc3d6bcdd Mon Sep 17 00:00:00 2001
From: mhucka <mhucka@google.com>
Date: Thu, 9 Jul 2026 17:09:45 +0000
Subject: [PATCH 12/42] Resolve pylint errors about import order

---
 .../resource_estimates/thc/utils/thc_factorization.py          | 2 +-
 src/openfermion/resource_estimates/thc/utils/thc_objectives.py | 3 +--
 2 files changed, 2 insertions(+), 3 deletions(-)

diff --git a/src/openfermion/resource_estimates/thc/utils/thc_factorization.py b/src/openfermion/resource_estimates/thc/utils/thc_factorization.py
index 899365b3e..f0db7d9a5 100644
--- a/src/openfermion/resource_estimates/thc/utils/thc_factorization.py
+++ b/src/openfermion/resource_estimates/thc/utils/thc_factorization.py
@@ -1,5 +1,5 @@
 # coverage:ignore
-# pylint: disable=wrong-import-position
+# pylint: disable=wrong-import-position,wrong-import-order
 import os
 
 from openfermion.config import get_available_cpu_count
diff --git a/src/openfermion/resource_estimates/thc/utils/thc_objectives.py b/src/openfermion/resource_estimates/thc/utils/thc_objectives.py
index d3488932d..d3d41e302 100644
--- a/src/openfermion/resource_estimates/thc/utils/thc_objectives.py
+++ b/src/openfermion/resource_estimates/thc/utils/thc_objectives.py
@@ -1,5 +1,5 @@
 # coverage:ignore
-# pylint: disable=wrong-import-position
+# pylint: disable=wrong-import-position,wrong-import-order
 import os
 
 from openfermion.config import get_available_cpu_count
@@ -24,7 +24,6 @@
 import numpy.random
 import numpy.linalg
 from scipy.optimize import minimize
-from openfermion.config import get_available_cpu_count
 from .adagrad import adagrad
 
 

From f08ba3451e69255669e146dd7471050ba23d5b05 Mon Sep 17 00:00:00 2001
From: Michael Hucka <mhucka@google.com>
Date: Thu, 9 Jul 2026 10:31:02 -0700
Subject: [PATCH 13/42] Update
 src/openfermion/resource_estimates/thc/utils/thc_factorization.py

Co-authored-by: gemini-code-assist[bot] <176961590+gemini-code-assist[bot]@users.noreply.github.com>
---
 .../resource_estimates/thc/utils/thc_factorization.py          | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/openfermion/resource_estimates/thc/utils/thc_factorization.py b/src/openfermion/resource_estimates/thc/utils/thc_factorization.py
index f0db7d9a5..419fde6bb 100644
--- a/src/openfermion/resource_estimates/thc/utils/thc_factorization.py
+++ b/src/openfermion/resource_estimates/thc/utils/thc_factorization.py
@@ -7,7 +7,8 @@
 # Set Intel MKL thread count for NumPy einsum/tensordot calls.
 # Needs to be set before other libraries are loaded.
 # Reduce count by 1 to lessen impact on host system.
-os.environ["MKL_NUM_THREADS"] = str(max(get_available_cpu_count() - 1, 1))
+if "MKL_NUM_THREADS" not in os.environ:
+    os.environ["MKL_NUM_THREADS"] = str(max(get_available_cpu_count() - 1, 1))
 
 
 from uuid import uuid4

From d0d1702a43747b18b982a7da72cba5a2e2f6db5f Mon Sep 17 00:00:00 2001
From: Michael Hucka <mhucka@google.com>
Date: Thu, 9 Jul 2026 10:31:10 -0700
Subject: [PATCH 14/42] Update
 src/openfermion/resource_estimates/thc/utils/thc_objectives.py

Co-authored-by: gemini-code-assist[bot] <176961590+gemini-code-assist[bot]@users.noreply.github.com>
---
 src/openfermion/resource_estimates/thc/utils/thc_objectives.py | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/openfermion/resource_estimates/thc/utils/thc_objectives.py b/src/openfermion/resource_estimates/thc/utils/thc_objectives.py
index d3d41e302..9ee605322 100644
--- a/src/openfermion/resource_estimates/thc/utils/thc_objectives.py
+++ b/src/openfermion/resource_estimates/thc/utils/thc_objectives.py
@@ -7,7 +7,8 @@
 # Set Intel MKL thread count for NumPy einsum/tensordot calls.
 # Needs to be set before other libraries are loaded.
 # Reduce count by 1 to lessen impact on host system.
-os.environ["MKL_NUM_THREADS"] = str(max(get_available_cpu_count() - 1, 1))
+if "MKL_NUM_THREADS" not in os.environ:
+    os.environ["MKL_NUM_THREADS"] = str(max(get_available_cpu_count() - 1, 1))
 
 
 from uuid import uuid4

From a288b96483c32d169ae907d9fe2a3aece227cf18 Mon Sep 17 00:00:00 2001
From: mhucka <mhucka@google.com>
Date: Thu, 9 Jul 2026 17:51:37 +0000
Subject: [PATCH 15/42] Fix merge conflicts

---
 .../resource_estimates/thc/utils/thc_factorization.py     | 8 +++-----
 .../resource_estimates/thc/utils/thc_objectives.py        | 8 +++-----
 2 files changed, 6 insertions(+), 10 deletions(-)

diff --git a/src/openfermion/resource_estimates/thc/utils/thc_factorization.py b/src/openfermion/resource_estimates/thc/utils/thc_factorization.py
index 419fde6bb..26b479482 100644
--- a/src/openfermion/resource_estimates/thc/utils/thc_factorization.py
+++ b/src/openfermion/resource_estimates/thc/utils/thc_factorization.py
@@ -2,13 +2,11 @@
 # pylint: disable=wrong-import-position,wrong-import-order
 import os
 
-from openfermion.config import get_available_cpu_count
+from openfermion.config import set_threading_limits
 
-# Set Intel MKL thread count for NumPy einsum/tensordot calls.
+# Set thread limits for NumPy einsum/tensordot calls.
 # Needs to be set before other libraries are loaded.
-# Reduce count by 1 to lessen impact on host system.
-if "MKL_NUM_THREADS" not in os.environ:
-    os.environ["MKL_NUM_THREADS"] = str(max(get_available_cpu_count() - 1, 1))
+set_threading_limits()
 
 
 from uuid import uuid4
diff --git a/src/openfermion/resource_estimates/thc/utils/thc_objectives.py b/src/openfermion/resource_estimates/thc/utils/thc_objectives.py
index 9ee605322..1e893f8b9 100644
--- a/src/openfermion/resource_estimates/thc/utils/thc_objectives.py
+++ b/src/openfermion/resource_estimates/thc/utils/thc_objectives.py
@@ -2,13 +2,11 @@
 # pylint: disable=wrong-import-position,wrong-import-order
 import os
 
-from openfermion.config import get_available_cpu_count
+from openfermion.config import set_threading_limits
 
-# Set Intel MKL thread count for NumPy einsum/tensordot calls.
+# Set thread limits for NumPy einsum/tensordot calls.
 # Needs to be set before other libraries are loaded.
-# Reduce count by 1 to lessen impact on host system.
-if "MKL_NUM_THREADS" not in os.environ:
-    os.environ["MKL_NUM_THREADS"] = str(max(get_available_cpu_count() - 1, 1))
+set_threading_limits()
 
 
 from uuid import uuid4

From 40ba3e8027a1946d4c8dc16e276de1035cc06275 Mon Sep 17 00:00:00 2001
From: mhucka <mhucka@google.com>
Date: Thu, 9 Jul 2026 17:50:01 +0000
Subject: [PATCH 16/42] Set OMP_NUM_THREADS and OPENBLAS_NUM_THREADS too

---
 src/openfermion/config.py      | 12 ++++++++++++
 src/openfermion/config_test.py | 25 +++++++++++++++++++++++++
 2 files changed, 37 insertions(+)

diff --git a/src/openfermion/config.py b/src/openfermion/config.py
index ab22adeb2..1fd43d41d 100644
--- a/src/openfermion/config.py
+++ b/src/openfermion/config.py
@@ -54,3 +54,15 @@ def get_available_cpu_count() -> int:
             pass
 
     return cpus
+
+
+def set_threading_limits() -> None:
+    """Sets thread limits for underlying numerical libraries (MKL, OpenBLAS, OMP).
+
+    This prevents libraries like NumPy, SciPy, and JAX from oversubscribing
+    available CPU resources on high-core-count or multi-worker environments.
+    """
+    limit = str(max(get_available_cpu_count() - 1, 1))
+    for var in ["MKL_NUM_THREADS", "OMP_NUM_THREADS", "OPENBLAS_NUM_THREADS"]:
+        if var not in os.environ:
+            os.environ[var] = limit
diff --git a/src/openfermion/config_test.py b/src/openfermion/config_test.py
index 966b17004..5224046f7 100644
--- a/src/openfermion/config_test.py
+++ b/src/openfermion/config_test.py
@@ -138,3 +138,28 @@ def test_set_threadpool_limits_fixture(self):
                 mock_threadpoolctl.threadpool_limits.assert_not_called()
                 with self.assertRaises(StopIteration):
                     next(gen)
+
+
+class SetThreadingLimitsTest(unittest.TestCase):
+
+    def test_set_threading_limits(self):
+        from openfermion.config import set_threading_limits
+        from unittest.mock import patch
+
+        # Clean/mocked environment dictionary.
+        env = {}
+        with patch.dict(os.environ, env, clear=True):
+            with patch("openfermion.config.get_available_cpu_count", return_value=8):
+                set_threading_limits()
+                self.assertEqual(os.environ.get("MKL_NUM_THREADS"), "7")
+                self.assertEqual(os.environ.get("OMP_NUM_THREADS"), "7")
+                self.assertEqual(os.environ.get("OPENBLAS_NUM_THREADS"), "7")
+
+        # Test respecting existing values.
+        env = {"OMP_NUM_THREADS": "3"}
+        with patch.dict(os.environ, env, clear=True):
+            with patch("openfermion.config.get_available_cpu_count", return_value=8):
+                set_threading_limits()
+                self.assertEqual(os.environ.get("MKL_NUM_THREADS"), "7")
+                self.assertEqual(os.environ.get("OMP_NUM_THREADS"), "3")  # Respected!
+                self.assertEqual(os.environ.get("OPENBLAS_NUM_THREADS"), "7")

From a9578069d50eed7f79db318493e82072615074f2 Mon Sep 17 00:00:00 2001
From: Michael Hucka <mhucka@google.com>
Date: Thu, 9 Jul 2026 10:56:15 -0700
Subject: [PATCH 17/42] Update src/openfermion/config.py

Co-authored-by: gemini-code-assist[bot] <176961590+gemini-code-assist[bot]@users.noreply.github.com>
---
 src/openfermion/config.py | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/src/openfermion/config.py b/src/openfermion/config.py
index 1fd43d41d..c12400d8b 100644
--- a/src/openfermion/config.py
+++ b/src/openfermion/config.py
@@ -62,7 +62,10 @@ def set_threading_limits() -> None:
     This prevents libraries like NumPy, SciPy, and JAX from oversubscribing
     available CPU resources on high-core-count or multi-worker environments.
     """
-    limit = str(max(get_available_cpu_count() - 1, 1))
+    if "PYTEST_XDIST_WORKER_COUNT" in os.environ:
+        limit = str(max(get_available_cpu_count(), 1))
+    else:
+        limit = str(max(get_available_cpu_count() - 1, 1))
     for var in ["MKL_NUM_THREADS", "OMP_NUM_THREADS", "OPENBLAS_NUM_THREADS"]:
         if var not in os.environ:
             os.environ[var] = limit

From 8a278eeba63f280fe9187180b3d5259665ee8523 Mon Sep 17 00:00:00 2001
From: mhucka <mhucka@google.com>
Date: Thu, 9 Jul 2026 18:02:42 +0000
Subject: [PATCH 18/42] Avoid inefficiency when num processes < 1

---
 src/openfermion/linalg/linear_qubit_operator.py      | 3 +++
 src/openfermion/linalg/linear_qubit_operator_test.py | 9 +++++++++
 2 files changed, 12 insertions(+)

diff --git a/src/openfermion/linalg/linear_qubit_operator.py b/src/openfermion/linalg/linear_qubit_operator.py
index 139878f35..6395b8972 100644
--- a/src/openfermion/linalg/linear_qubit_operator.py
+++ b/src/openfermion/linalg/linear_qubit_operator.py
@@ -186,6 +186,9 @@ def _matvec(self, x):
         if not self.linear_operators:
             return numpy.zeros(x.shape)
 
+        if self.options.processes <= 1:
+            return functools.reduce(numpy.add, (operator * x for operator in self.linear_operators))
+
         pool = self.options.get_pool(len(self.linear_operators))
         vecs = pool.imap_unordered(
             apply_operator, [(operator, x) for operator in self.linear_operators]
diff --git a/src/openfermion/linalg/linear_qubit_operator_test.py b/src/openfermion/linalg/linear_qubit_operator_test.py
index 7b31113a9..cd9f7d005 100644
--- a/src/openfermion/linalg/linear_qubit_operator_test.py
+++ b/src/openfermion/linalg/linear_qubit_operator_test.py
@@ -262,6 +262,15 @@ def test_closed_workers_not_reused(self):
         parallel_qubit_op.dot(state)
         self.assertIsNone(parallel_qubit_op.options.pool)
 
+    def test_matvec_single_process(self):
+        """Tests that when processes is 1, it computes correctly and doesn't crash."""
+        qubit_operator = QubitOperator('Z3') + QubitOperator('Y0') + QubitOperator('X1')
+        options = LinearQubitOperatorOptions(processes=1)
+        parallel_qubit_op = ParallelLinearQubitOperator(
+            qubit_operator, self.n_qubits, options=options
+        )
+        self.assertTrue(numpy.allclose(parallel_qubit_op * self.vec, self.expected_matvec))
+
 
 class UtilityFunctionTest(unittest.TestCase):
     """Tests for utility functions."""

From 2768ebbd168f642dfa7f7d2cee760b7fcd6b30fc Mon Sep 17 00:00:00 2001
From: Michael Hucka <mhucka@google.com>
Date: Thu, 9 Jul 2026 11:07:27 -0700
Subject: [PATCH 19/42] Update src/openfermion/config.py

Co-authored-by: gemini-code-assist[bot] <176961590+gemini-code-assist[bot]@users.noreply.github.com>
---
 src/openfermion/config.py | 1 -
 1 file changed, 1 deletion(-)

diff --git a/src/openfermion/config.py b/src/openfermion/config.py
index c12400d8b..781b52bed 100644
--- a/src/openfermion/config.py
+++ b/src/openfermion/config.py
@@ -48,7 +48,6 @@ def get_available_cpu_count() -> int:
         try:
             worker_count = int(os.environ["PYTEST_XDIST_WORKER_COUNT"])
             if worker_count > 0:
-                # cpus = max(1, (cpus - 1) // worker_count)
                 cpus = max(1, cpus // worker_count)
         except ValueError:
             pass

From 6f8fdff8a7e11aaff3285288c3df48ca25c7b544 Mon Sep 17 00:00:00 2001
From: mhucka <mhucka@google.com>
Date: Thu, 9 Jul 2026 18:23:59 +0000
Subject: [PATCH 20/42] Set threading limits here too

---
 conftest.py | 16 +++++++++++-----
 1 file changed, 11 insertions(+), 5 deletions(-)

diff --git a/conftest.py b/conftest.py
index 6dafd7443..31caabe2c 100644
--- a/conftest.py
+++ b/conftest.py
@@ -1,3 +1,4 @@
+# pylint: disable=wrong-import-position,wrong-import-order
 #   Licensed under the Apache License, Version 2.0 (the "License");
 #   you may not use this file except in compliance with the License.
 #   You may obtain a copy of the License at
@@ -11,17 +12,22 @@
 #   limitations under the License.
 
 import os
-import random
 import sys
-from typing import Any
-
-import numpy as np
-import pytest
 
 # Ensure src/ is in sys.path so that the OpenFermion utils module can be
 # imported at Pytest startup time.
 sys.path.insert(0, os.path.abspath(os.path.join(os.path.dirname(__file__), "src")))
 
+from openfermion.config import set_threading_limits
+
+set_threading_limits()
+
+import random
+from typing import Any
+
+import numpy as np
+import pytest
+
 
 def pytest_configure(config: Any) -> None:
     # Set seeds for collection-time parameterization.

From 81ae963d324d71d81838ac95d39aa416c64208c0 Mon Sep 17 00:00:00 2001
From: mhucka <mhucka@google.com>
Date: Thu, 9 Jul 2026 18:48:07 +0000
Subject: [PATCH 21/42] Add more test coverage

---
 src/openfermion/config_test.py | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/src/openfermion/config_test.py b/src/openfermion/config_test.py
index 5224046f7..0158ab8e6 100644
--- a/src/openfermion/config_test.py
+++ b/src/openfermion/config_test.py
@@ -163,3 +163,12 @@ def test_set_threading_limits(self):
                 self.assertEqual(os.environ.get("MKL_NUM_THREADS"), "7")
                 self.assertEqual(os.environ.get("OMP_NUM_THREADS"), "3")  # Respected!
                 self.assertEqual(os.environ.get("OPENBLAS_NUM_THREADS"), "7")
+
+        # Test when PYTEST_XDIST_WORKER_COUNT is in os.environ (line 65 coverage).
+        env = {"PYTEST_XDIST_WORKER_COUNT": "4"}
+        with patch.dict(os.environ, env, clear=True):
+            with patch("openfermion.config.get_available_cpu_count", return_value=8):
+                set_threading_limits()
+                self.assertEqual(os.environ.get("MKL_NUM_THREADS"), "8")
+                self.assertEqual(os.environ.get("OMP_NUM_THREADS"), "8")
+                self.assertEqual(os.environ.get("OPENBLAS_NUM_THREADS"), "8")

From 1832e6e3929787a0affcf5dc213c9befaef62401 Mon Sep 17 00:00:00 2001
From: mhucka <mhucka@google.com>
Date: Fri, 10 Jul 2026 01:05:54 +0000
Subject: [PATCH 22/42] Update `CONTRIBUTING.md` and fix errors

---
 CONTRIBUTING.md | 28 ++++++++++++----------------
 1 file changed, 12 insertions(+), 16 deletions(-)

diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index a6dd7f993..e6f67fe38 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -241,10 +241,6 @@ to run it:
 check/mypy
 ```
 
-If your computer has multiple processor cores, you can add the option `-j 0` to the command above to
-make Mypy run in parallel for a substantial speed increase.
-
-
 ### Linting and formatting
 
 Code should meet common style standards for Python and be free of error-prone constructs. We use
@@ -290,14 +286,15 @@ tests, follow these general principles:
     messages.
 
 We use [pytest](https://docs.pytest.org) to run our tests and
-[pytest-cov](https://pytest-cov.readthedocs.io) to compute coverage.
+[pytest-cov](https://pytest-cov.readthedocs.io) to compute coverage. There are wrapper scripts
+in the `check/` subdirectory to run these programs.
 
-*   While developing, periodically check that changes do not break anything. For fast checks, use
-    `pytest -m "not slow" PATH`, where `PATH` is a directory or pytest file to test.
+*   During development, periodically check that code changes do not break anything. For fast checks,
+    run `check/pytest -m "not slow" -n auto PATH ...`, where `PATH ...` is one or more directories
+    or `_test.py` files to test. (The `-n auto` option makes pytest use parallel processes; omit it
+    if it causes problems on your system.)
 
-*   After finishing a task, run `check/pytest` to test all of the OpenFermion code. If your system
-    has multiple processor cores, you can add the option `-n auto` to make pytest use multiple
-    parallel processes for a speed increase. (Beware, though, that this is resource-intensive.)
+*   After finishing a task, run all tests with `check/pytest -n auto`.
 
 We don't require 100% coverage, but coverage should be very high, and any uncovered code must be
 annotated with `# pragma: no cover`. To ignore coverage of a single line, place `# pragma: no cover`
@@ -306,13 +303,12 @@ cover` comment on its own line. Note, however, that these annotations should be
 
 ### Final checks
 
-After a task is finished, run each of the following to make sure everything passes all the tests:
+After the work planned for a pull request is finished, run each of the following to make sure
+everything passes all tests:
 
-*   `check/format-incremental` (and `check/format-incremental --apply` to auto-fix format problems)
-*   `check/pylint -j 0`
-*   `check/mypy`
-*   `check/pytest -n auto`
-*   `check/pytest-and-incremental-coverage`
+```shell
+check/all
+```
 
 ### Pull requests and code reviews
 

From b51b431747e6163365541d10ad96ecf99db5812a Mon Sep 17 00:00:00 2001
From: mhucka <mhucka@google.com>
Date: Fri, 10 Jul 2026 01:50:17 +0000
Subject: [PATCH 23/42] Don't pass --jobs=0 to pylint by default

This was inconsistent with check/pylint.
---
 check/pylint-changed-files | 45 ++++++++++++++++++++++++--------------
 1 file changed, 28 insertions(+), 17 deletions(-)

diff --git a/check/pylint-changed-files b/check/pylint-changed-files
index 69500932a..c3248ad31 100755
--- a/check/pylint-changed-files
+++ b/check/pylint-changed-files
@@ -43,25 +43,36 @@ thisdir=$(dirname "${BASH_SOURCE[0]:?}") || exit $?
 repo_dir=$(git -C "${thisdir}" rev-parse --show-toplevel) || exit $?
 cd "${repo_dir}" || exit $?
 
-# Figure out which revision to compare against.
-if [ -n "$1" ] && [[ $1 != -* ]]; then
-    if ! git rev-parse --verify --quiet --no-revs "$1^{commit}"; then
-        echo -e "\033[31mNo revision '$1'.\033[0m" >&2
+# Figure out which revision to compare against and gather other arguments.
+declare -a pylint_args=()
+rev=""
+
+for arg in "$@"; do
+    if [[ "${arg}" == -* ]]; then
+        pylint_args+=( "${arg}" )
+    elif [[ -z "${rev}" ]] &&
+        git rev-parse --verify --quiet --no-revs "${arg}^{commit}" &> /dev/null; then
+        rev="${arg}"
+    else
+        pylint_args+=( "${arg}" )
+    fi
+done
+
+if [[ -z "${rev}" ]]; then
+    if [[ "$(git cat-file -t "upstream/main" 2> /dev/null)" == "commit" ]]; then
+        rev=upstream/main
+    elif [[ "$(git cat-file -t "origin/main" 2> /dev/null)" == "commit" ]]; then
+        rev=origin/main
+    elif [[ "$(git cat-file -t "main" 2> /dev/null)" == "commit" ]]; then
+        rev=main
+    else
+        echo -e "\033[31mNo default revision found to compare against. \
+Please specify a base revision (e.g. 'origin/main' or 'HEAD~1') as an argument.\033[0m" >&2
         exit 1
     fi
-    rev=$1
-elif [ "$(git cat-file -t "upstream/main" 2> /dev/null)" == "commit" ]; then
-    rev=upstream/main
-elif [ "$(git cat-file -t "origin/main" 2> /dev/null)" == "commit" ]; then
-    rev=origin/main
-elif [ "$(git cat-file -t "main" 2> /dev/null)" == "commit" ]; then
-    rev=main
-else
-    echo -e "\033[31mNo default revision found to compare against. Argument #1 must be what to diff against (e.g. 'origin/main' or 'HEAD~1').\033[0m" >&2
-    exit 1
 fi
 base=$(git merge-base "${rev}" HEAD)
-if [ "$(git rev-parse "${rev}")" == "${base}" ]; then
+if [[ "$(git rev-parse "${rev}")" == "${base}" ]]; then
     echo -e "Comparing against revision '${rev}'." >&2
 else
     echo -e "Comparing against revision '${rev}' (merge base ${base})." >&2
@@ -78,7 +89,7 @@ num_changed=${#changed[@]}
 
 # Run it.
 echo "Found ${num_changed} lintable files associated with changes." >&2
-if [ "${num_changed}" -eq 0 ]; then
+if [[ "${num_changed}" -eq 0 ]]; then
     exit 0
 fi
-env PYTHONPATH=dev_tools pylint --jobs=0 "${changed[@]}"
+env PYTHONPATH=dev_tools pylint "${pylint_args[@]}" "${changed[@]}"

From 61c3b0a3597dd8833dab7de1de813962dcbbdc93 Mon Sep 17 00:00:00 2001
From: mhucka <mhucka@google.com>
Date: Fri, 10 Jul 2026 02:04:17 +0000
Subject: [PATCH 24/42] Don't pass `-n auto` by default and update script

---
 check/pytest-and-incremental-coverage | 51 ++++++++++++++++-----------
 1 file changed, 30 insertions(+), 21 deletions(-)

diff --git a/check/pytest-and-incremental-coverage b/check/pytest-and-incremental-coverage
index ed6c1e506..77c0a5e23 100755
--- a/check/pytest-and-incremental-coverage
+++ b/check/pytest-and-incremental-coverage
@@ -36,30 +36,39 @@
 ################################################################################
 
 # Get the working directory to the repo root.
-cd "$( dirname "${BASH_SOURCE[0]}" )" || exit 1
+cd "$(dirname "${BASH_SOURCE[0]}")" || exit 1
 cd "$(git rev-parse --show-toplevel)" || exit 1
 
-# Figure out which revision to compare against.
-if [[ -n "$1" && $1 != -* ]]; then
-    if [[ "$(git cat-file -t "$1" 2> /dev/null)" != "commit" ]]; then
-        echo -e "\033[31mNo revision '$1'.\033[0m" >&2
+# Figure out which revision to compare against and gather other arguments.
+declare -a pytest_args=()
+rev=""
+
+for arg in "$@"; do
+    if [[ "${arg}" == -* ]]; then
+        pytest_args+=( "${arg}" )
+    elif [[ -z "${rev}" ]] &&
+        git rev-parse --verify --quiet --no-revs "${arg}^{commit}" &> /dev/null; then
+        rev="${arg}"
+    else
+        pytest_args+=( "${arg}" )
+    fi
+done
+
+if [[ -z "${rev}" ]]; then
+    if [[ "$(git cat-file -t upstream/main 2> /dev/null)" == "commit" ]]; then
+        rev=upstream/main
+    elif [[ "$(git cat-file -t origin/main 2> /dev/null)" == "commit" ]]; then
+        rev=origin/main
+    elif [[ "$(git cat-file -t main 2> /dev/null)" == "commit" ]]; then
+        rev=main
+    else
+        echo -e "\033[31mNo default revision found to compare against. \
+Please specify a base revision (e.g. 'origin/main' or 'HEAD~1') as an argument.\033[0m" >&2
         exit 1
     fi
-    rev=$1
-elif [ "$(git cat-file -t upstream/main 2> /dev/null)" == "commit" ]; then
-    rev=upstream/main
-elif [ "$(git cat-file -t origin/main 2> /dev/null)" == "commit" ]; then
-    rev=origin/main
-elif [ "$(git cat-file -t main 2> /dev/null)" == "commit" ]; then
-    rev=main
-else
-    echo -e "\033[31mNo default revision found to compare against. Argument #1 must be what to diff against (e.g. 'origin/main' or 'HEAD~1').\033[0m" >&2
-    exit 1
 fi
-# shellcheck disable=SC2086
-base="$(git merge-base ${rev} HEAD)"
-# shellcheck disable=SC2086
-if [ "$(git rev-parse ${rev})" == "${base}" ]; then
+base="$(git merge-base "${rev}" HEAD)"
+if [[ "$(git rev-parse "${rev}")" == "${base}" ]]; then
     echo -e "Comparing against revision '${rev}'." >&2
 else
     echo -e "Comparing against revision '${rev}' (merge base ${base})." >&2
@@ -68,7 +77,7 @@ fi
 
 # Run tests while producing coverage files.
 check/pytest . \
-    -n auto \
+    "${pytest_args[@]}" \
     --actually-quiet \
     --cov \
     --cov-report=annotate
@@ -82,7 +91,7 @@ cover_result=$?
 find . | grep "\.py,cover$" | xargs rm -f
 
 # Report result.
-if [ "${pytest_result}" -ne "0" ] || [ "${cover_result}" -ne "0" ]; then
+if [[ "${pytest_result}" -ne "0" ]] || [[ "${cover_result}" -ne "0" ]]; then
   exit 1
 fi
 exit 0

From aa6d6373374cf354df200e16362fee42497948e6 Mon Sep 17 00:00:00 2001
From: mhucka <mhucka@google.com>
Date: Fri, 10 Jul 2026 02:58:52 +0000
Subject: [PATCH 25/42] Set the thread variables unconditionally

---
 src/openfermion/config.py | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/openfermion/config.py b/src/openfermion/config.py
index 781b52bed..5347af088 100644
--- a/src/openfermion/config.py
+++ b/src/openfermion/config.py
@@ -66,5 +66,4 @@ def set_threading_limits() -> None:
     else:
         limit = str(max(get_available_cpu_count() - 1, 1))
     for var in ["MKL_NUM_THREADS", "OMP_NUM_THREADS", "OPENBLAS_NUM_THREADS"]:
-        if var not in os.environ:
-            os.environ[var] = limit
+        os.environ[var] = limit

From 02c43920d28a6cd233abd31215b8ca199cab5f57 Mon Sep 17 00:00:00 2001
From: mhucka <mhucka@google.com>
Date: Fri, 10 Jul 2026 03:05:43 +0000
Subject: [PATCH 26/42] Take out conditional setting of the threads variables

---
 src/openfermion/config_test.py | 18 ++++++++----------
 1 file changed, 8 insertions(+), 10 deletions(-)

diff --git a/src/openfermion/config_test.py b/src/openfermion/config_test.py
index 0158ab8e6..303681343 100644
--- a/src/openfermion/config_test.py
+++ b/src/openfermion/config_test.py
@@ -155,16 +155,7 @@ def test_set_threading_limits(self):
                 self.assertEqual(os.environ.get("OMP_NUM_THREADS"), "7")
                 self.assertEqual(os.environ.get("OPENBLAS_NUM_THREADS"), "7")
 
-        # Test respecting existing values.
-        env = {"OMP_NUM_THREADS": "3"}
-        with patch.dict(os.environ, env, clear=True):
-            with patch("openfermion.config.get_available_cpu_count", return_value=8):
-                set_threading_limits()
-                self.assertEqual(os.environ.get("MKL_NUM_THREADS"), "7")
-                self.assertEqual(os.environ.get("OMP_NUM_THREADS"), "3")  # Respected!
-                self.assertEqual(os.environ.get("OPENBLAS_NUM_THREADS"), "7")
-
-        # Test when PYTEST_XDIST_WORKER_COUNT is in os.environ (line 65 coverage).
+        # Test when PYTEST_XDIST_WORKER_COUNT is in os.environ.
         env = {"PYTEST_XDIST_WORKER_COUNT": "4"}
         with patch.dict(os.environ, env, clear=True):
             with patch("openfermion.config.get_available_cpu_count", return_value=8):
@@ -172,3 +163,10 @@ def test_set_threading_limits(self):
                 self.assertEqual(os.environ.get("MKL_NUM_THREADS"), "8")
                 self.assertEqual(os.environ.get("OMP_NUM_THREADS"), "8")
                 self.assertEqual(os.environ.get("OPENBLAS_NUM_THREADS"), "8")
+
+        # Test when there are existing values.
+        env = {"OMP_NUM_THREADS": "3"}
+        with patch.dict(os.environ, env, clear=True):
+            with patch("openfermion.config.get_available_cpu_count", return_value=8):
+                set_threading_limits()
+                self.assertEqual(os.environ.get("OMP_NUM_THREADS"), "7")

From 3918f93a61aba90fbc76dc90ffecad8f1ad3ae1f Mon Sep 17 00:00:00 2001
From: mhucka <mhucka@google.com>
Date: Fri, 10 Jul 2026 03:15:13 +0000
Subject: [PATCH 27/42] Change handling of parallelism in check/all

---
 check/all | 80 +++++++++++++++++++++++++++++++++++--------------------
 1 file changed, 51 insertions(+), 29 deletions(-)

diff --git a/check/all b/check/all
index 1a09b79cc..1111a4d2a 100755
--- a/check/all
+++ b/check/all
@@ -17,22 +17,34 @@
 # This script is modeled in part on Cirq's check/all script.
 
 declare -r usage="\
-Usage: ${0##*/} [--help] [--only-changed-files] [--apply-format-changes] [BASE_REV]
+Usage: ${0##*/} [OPTIONS] [BASE_REV]
 
-If the first argument given on the command line is the option --help or -h,
-this program prints usage information and then exits.
-
-With no arguments, this runs multiple checks on the code base. These tests
-are based on the programs in the checks/ subdirectory.
+Runs multiple checks on the code base.
 
-If --apply-format-changes is specified, the flag --apply will be passed to
-check/format-incremental to apply the format changes suggested by the
+If --apply-changes (or -a) is given, the flag --apply will be passed to
+check/format-incremental to make it apply format changes suggested by the
 formatter.
 
-You can specify a base git revision to compare against (i.e., to use when
-determining whether or not a file is considered to have changed). If given,
-the argument BASE_REV is passed on to tests that can use it, such as
-check/pytest-and-incremental-coverage."
+If --only-changed-files (or -c) is given, most checks will be limited to the
+files that have changed since the BASE_REV version. If BASE_REV is not given,
+the version at the end of the base branch (origin/main) will be used.
+
+By default, this program runs checks in parallel mode. To prevent this, use the
+option --no-parallel (or -p).
+
+You can specify a base git revision to compare against (that is, the revision
+to be used when determining whether a file is considered to have changed). If
+given, the argument BASE_REV is passed on to tests that can use it, such as
+check/pytest-and-incremental-coverage.
+
+If the first argument given on the command line is the option --help or -h,
+this program prints usage information and then exits.
+
+Summary of available options:
+  --apply-changes       Pass the flag --apply to check/format-incremental
+  --no-parallel         Do not pass the parallelism flags to the check programs
+  --only-changed-files  Limit checks to files that have changed since BASE_REV
+  -h or --help          Show this help message and exit"
 
 set -eo pipefail -o errtrace
 shopt -s inherit_errexit
@@ -51,53 +63,63 @@ function error() {
 declare -a rev=()
 declare -a apply_arg=()
 declare only_changed=""
-for arg in "$@"; do
-    case "${arg}" in
+declare no_parallel=""
+
+while [[ $# -gt 0 ]]; do
+    case "$1" in
+        -a | --apply-changes | --apply-format-changes)
+            apply_arg=( "--apply" )
+            ;;
+        -c | --only-changed-files)
+            only_changed="true"
+            ;;
         -h | --help)
             echo "${usage}"
             exit 0
             ;;
-        --apply-format-changes)
-            apply_arg=( "--apply" )
-            shift
-            ;;
-        --only-changed-files)
-            only_changed="true"
-            shift
+        -p | --no-parallel)
+            no_parallel="true"
             ;;
         -*)
-            error "Invalid option '${arg}'"
+            error "Invalid option '$1'"
             error "See '$0 --help' for the list of supported options."
             exit 1
             ;;
         *)
-            if ! rev=( "$(git rev-parse --verify --end-of-options "${arg}^{commit}")" ); then
-                error "No revision '${arg}'"
+            if ! rev=( "$(git rev-parse --verify --end-of-options "$1^{commit}")" ); then
+                error "No revision '$1'"
                 exit 1
             fi
             ;;
     esac
+    shift
 done
 
 # ~~~~ Run the tests ~~~~
 
 declare -a errors=()
+declare -a pylint_j=()
+declare -a pytest_n=()
 
 function run() {
-    echo "Running $* ..."
+    echo "Running $*"
     "$@" || errors+=( "$* failed" )
-    echo
 }
 
+if [[ -z "${no_parallel}" ]]; then
+    pylint_j=("-j0")
+    pytest_n=("-n" "auto")
+fi
+
 if [[ -n "${only_changed}" ]]; then
     run check/format-incremental "${rev[@]}" "${apply_arg[@]}"
-    run check/pylint-changed-files "${rev[@]}"
+    run check/pylint-changed-files "${pylint_j[@]}" "${rev[@]}"
 else
     run check/format-incremental "${rev[@]}" "${apply_arg[@]}" --all
-    run check/pylint "${rev[@]}"
+    run check/pylint "${pylint_j[@]}" "${rev[@]}"
 fi
 run check/mypy
-run check/pytest-and-incremental-coverage "${rev[@]}"
+run check/pytest-and-incremental-coverage "${pytest_n[@]}" "${rev[@]}"
 run check/shellcheck
 run check/nbformat
 

From 79146487be07e01b3b4b68243522d63097005273 Mon Sep 17 00:00:00 2001
From: mhucka <mhucka@google.com>
Date: Fri, 10 Jul 2026 03:52:52 +0000
Subject: [PATCH 28/42] Add threadpoolctl to the pytest dependencies

---
 dev_tools/requirements/deps/pytest.txt | 1 +
 1 file changed, 1 insertion(+)

diff --git a/dev_tools/requirements/deps/pytest.txt b/dev_tools/requirements/deps/pytest.txt
index 0dca16a9f..c56b085c8 100644
--- a/dev_tools/requirements/deps/pytest.txt
+++ b/dev_tools/requirements/deps/pytest.txt
@@ -7,3 +7,4 @@ pytest-xdist
 
 nbformat
 tensorflow-docs
+threadpoolctl

From db7309b5b144aaa956fe5f9414cd2996563c21d3 Mon Sep 17 00:00:00 2001
From: mhucka <mhucka@google.com>
Date: Fri, 10 Jul 2026 03:56:05 +0000
Subject: [PATCH 29/42] Use different number of items for affinity test

Adjusted a test per review comment from Adam R.
---
 src/openfermion/config_test.py | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/openfermion/config_test.py b/src/openfermion/config_test.py
index 303681343..c0fd7f79f 100644
--- a/src/openfermion/config_test.py
+++ b/src/openfermion/config_test.py
@@ -55,9 +55,9 @@ def test_get_available_cpu_count_various_os(self):
             self.assertEqual(get_available_cpu_count(), 1)
 
         # Test Case 2: Linux/Unix (no process_cpu_count, has sched_getaffinity).
-        mock_os = MockOS(sched_getaffinity_val=[1, 2, 3, 4])
+        mock_os = MockOS(sched_getaffinity_val=[1, 2, 3])
         with patch.object(config, "os", mock_os):
-            self.assertEqual(get_available_cpu_count(), 4)
+            self.assertEqual(get_available_cpu_count(), 3)
 
         # Test Case 3: Linux/Unix but sched_getaffinity raises exception.
         mock_os = MockOS(sched_getaffinity_val=ValueError("error"), cpu_count_val=4)

From e6fa64fa5f49e2a762a522196177a4ad9fe1dc1f Mon Sep 17 00:00:00 2001
From: mhucka <mhucka@google.com>
Date: Fri, 10 Jul 2026 03:58:26 +0000
Subject: [PATCH 30/42] Regenerate requirements files

---
 dev_tools/requirements/envs/dev.env.txt       |   4 +
 dev_tools/requirements/envs/pylint.env.txt    |   6 +
 .../requirements/envs/pytest-extra.env.txt    |   6 +
 dev_tools/requirements/envs/pytest.env.txt    |   6 +
 .../max_compat/pytest-max-compat.env.txt      | 206 +++++-------------
 5 files changed, 72 insertions(+), 156 deletions(-)

diff --git a/dev_tools/requirements/envs/dev.env.txt b/dev_tools/requirements/envs/dev.env.txt
index f1c4bc2ad..b6abff1a0 100644
--- a/dev_tools/requirements/envs/dev.env.txt
+++ b/dev_tools/requirements/envs/dev.env.txt
@@ -2018,6 +2018,10 @@ sympy==1.14.0 \
 tensorflow-docs==2025.2.19.33219 \
     --hash=sha256:b52682f3739110ce804af701f9ab5ac1efe07760109a5b5640769851d7d14b19
     # via -r dev_tools/requirements/deps/pytest.txt
+threadpoolctl==3.6.0 \
+    --hash=sha256:43a0b8fd5a2928500110039e43a5eed8480b918967083ea48dc3ab9f13c4a7fb \
+    --hash=sha256:8ab8b4aa3491d812b623328249fab5302a68d2d71745c8a4c719a2fcaba9f44e
+    # via -r dev_tools/requirements/deps/pytest.txt
 tomli==2.4.1 ; python_full_version <= '3.11' \
     --hash=sha256:01f520d4f53ef97964a240a035ec2a869fe1a37dde002b57ebc4417a27ccd853 \
     --hash=sha256:0d85819802132122da43cb86656f8d1f8c6587d54ae7dcaf30e90533028b49fe \
diff --git a/dev_tools/requirements/envs/pylint.env.txt b/dev_tools/requirements/envs/pylint.env.txt
index 5868211c4..906531b76 100644
--- a/dev_tools/requirements/envs/pylint.env.txt
+++ b/dev_tools/requirements/envs/pylint.env.txt
@@ -1578,6 +1578,12 @@ tensorflow-docs==2025.2.19.33219 \
     # via
     #   -c dev_tools/requirements/envs/dev.env.txt
     #   -r dev_tools/requirements/deps/pytest.txt
+threadpoolctl==3.6.0 \
+    --hash=sha256:43a0b8fd5a2928500110039e43a5eed8480b918967083ea48dc3ab9f13c4a7fb \
+    --hash=sha256:8ab8b4aa3491d812b623328249fab5302a68d2d71745c8a4c719a2fcaba9f44e
+    # via
+    #   -c dev_tools/requirements/envs/dev.env.txt
+    #   -r dev_tools/requirements/deps/pytest.txt
 tomli==2.4.1 ; python_full_version <= '3.11' \
     --hash=sha256:01f520d4f53ef97964a240a035ec2a869fe1a37dde002b57ebc4417a27ccd853 \
     --hash=sha256:0d85819802132122da43cb86656f8d1f8c6587d54ae7dcaf30e90533028b49fe \
diff --git a/dev_tools/requirements/envs/pytest-extra.env.txt b/dev_tools/requirements/envs/pytest-extra.env.txt
index acce1f0dd..147da67ee 100644
--- a/dev_tools/requirements/envs/pytest-extra.env.txt
+++ b/dev_tools/requirements/envs/pytest-extra.env.txt
@@ -1546,6 +1546,12 @@ tensorflow-docs==2025.2.19.33219 \
     # via
     #   -c dev_tools/requirements/envs/dev.env.txt
     #   -r dev_tools/requirements/deps/pytest.txt
+threadpoolctl==3.6.0 \
+    --hash=sha256:43a0b8fd5a2928500110039e43a5eed8480b918967083ea48dc3ab9f13c4a7fb \
+    --hash=sha256:8ab8b4aa3491d812b623328249fab5302a68d2d71745c8a4c719a2fcaba9f44e
+    # via
+    #   -c dev_tools/requirements/envs/dev.env.txt
+    #   -r dev_tools/requirements/deps/pytest.txt
 tomli==2.4.1 ; python_full_version <= '3.11' \
     --hash=sha256:01f520d4f53ef97964a240a035ec2a869fe1a37dde002b57ebc4417a27ccd853 \
     --hash=sha256:0d85819802132122da43cb86656f8d1f8c6587d54ae7dcaf30e90533028b49fe \
diff --git a/dev_tools/requirements/envs/pytest.env.txt b/dev_tools/requirements/envs/pytest.env.txt
index afad91589..b116bc55b 100644
--- a/dev_tools/requirements/envs/pytest.env.txt
+++ b/dev_tools/requirements/envs/pytest.env.txt
@@ -1433,6 +1433,12 @@ tensorflow-docs==2025.2.19.33219 \
     # via
     #   -c dev_tools/requirements/envs/dev.env.txt
     #   -r dev_tools/requirements/deps/pytest.txt
+threadpoolctl==3.6.0 \
+    --hash=sha256:43a0b8fd5a2928500110039e43a5eed8480b918967083ea48dc3ab9f13c4a7fb \
+    --hash=sha256:8ab8b4aa3491d812b623328249fab5302a68d2d71745c8a4c719a2fcaba9f44e
+    # via
+    #   -c dev_tools/requirements/envs/dev.env.txt
+    #   -r dev_tools/requirements/deps/pytest.txt
 tomli==2.4.1 ; python_full_version <= '3.11' \
     --hash=sha256:01f520d4f53ef97964a240a035ec2a869fe1a37dde002b57ebc4417a27ccd853 \
     --hash=sha256:0d85819802132122da43cb86656f8d1f8c6587d54ae7dcaf30e90533028b49fe \
diff --git a/dev_tools/requirements/max_compat/pytest-max-compat.env.txt b/dev_tools/requirements/max_compat/pytest-max-compat.env.txt
index 30789a0db..082214d2c 100644
--- a/dev_tools/requirements/max_compat/pytest-max-compat.env.txt
+++ b/dev_tools/requirements/max_compat/pytest-max-compat.env.txt
@@ -3,35 +3,26 @@
 absl-py==2.4.0 \
     --hash=sha256:88476fd881ca8aab94ffa78b7b6c632a782ab3ba1cd19c9bd423abc4fb4cd28d \
     --hash=sha256:8c6af82722b35cf71e0f4d1d47dcaebfff286e27110a99fc359349b247dfb5d4
-    # via
-    #   -c dev_tools/requirements/max_compat/dev.env.txt
-    #   tensorflow-docs
+    # via tensorflow-docs
 astor==0.8.1 \
     --hash=sha256:070a54e890cefb5b3739d19f30f5a5ec840ffc9c50ffa7d23cc9fc1a38ebbfc5 \
     --hash=sha256:6a6effda93f4e1ce9f618779b2dd1d9d84f1e32812c23a29b3fff6fd7f63fa5e
-    # via
-    #   -c dev_tools/requirements/max_compat/dev.env.txt
-    #   tensorflow-docs
+    # via tensorflow-docs
 attrs==26.1.0 \
     --hash=sha256:c647aa4a12dfbad9333ca4e71fe62ddc36f4e63b2d260a37a8b83d2f043ac309 \
     --hash=sha256:d03ceb89cb322a8fd706d4fb91940737b6642aa36998fe130a9bc96c985eff32
     # via
-    #   -c dev_tools/requirements/max_compat/dev.env.txt
     #   cirq-core
     #   jsonschema
     #   referencing
 backports-asyncio-runner==1.2.0 ; python_full_version < '3.11' \
     --hash=sha256:0da0a936a8aeb554eccb426dc55af3ba63bcdc69fa1a600b5bb305413a4477b5 \
     --hash=sha256:a5aa7b2b7d8f8bfcaa2b57313f70792df84e32a2a746f585213373f900b42162
-    # via
-    #   -c dev_tools/requirements/max_compat/dev.env.txt
-    #   pytest-asyncio
+    # via pytest-asyncio
 certifi==2026.5.20 \
     --hash=sha256:3c52e209ba0a4ad7aebe60436a4ab349c39e1e602e8c134221e546902ad25897 \
     --hash=sha256:69dea482ab64caa7b9f6aba1c6bf48bb6a5448d1c0f1b17ab42ad8c763a5344d
-    # via
-    #   -c dev_tools/requirements/max_compat/dev.env.txt
-    #   requests
+    # via requests
 charset-normalizer==3.4.7 \
     --hash=sha256:007d05ec7321d12a40227aae9e2bc6dca73f3cb21058999a1df9e193555a9dcc \
     --hash=sha256:03853ed82eeebbce3c2abfdbc98c96dc205f32a79627688ac9a27370ea61a49c \
@@ -162,26 +153,21 @@ charset-normalizer==3.4.7 \
     --hash=sha256:f59ad4c0e8f6bba240a9bb85504faa1ab438237199d4cce5f622761507b8f6a6 \
     --hash=sha256:fbccdc05410c9ee21bbf16a35f4c1d16123dcdeb8a1d38f33654fa21d0234f79 \
     --hash=sha256:fea24543955a6a729c45a73fe90e08c743f0b3334bbf3201e6c4bc1b0c7fa464
-    # via
-    #   -c dev_tools/requirements/max_compat/dev.env.txt
-    #   requests
+    # via requests
 cirq-core==1.4.1 ; python_full_version < '3.11' \
     --hash=sha256:869db60413265c41a8206854c1d4ca9bad5fac9cfd7c6a10685b5a6d516defa0
     # via
     #   -c dev_tools/requirements/deps/oldest-versions.txt
-    #   -c dev_tools/requirements/max_compat/dev.env.txt
     #   -r dev_tools/requirements/deps/runtime.txt
 cirq-core==1.6.1 ; python_full_version >= '3.11' \
     --hash=sha256:fbc809d7c6a228762ad92bb7870dc16f55b76728fcc7ef4c7aaceb7e5c63e8e6
     # via
     #   -c dev_tools/requirements/deps/oldest-versions.txt
-    #   -c dev_tools/requirements/max_compat/dev.env.txt
     #   -r dev_tools/requirements/deps/runtime.txt
 colorama==0.4.6 ; sys_platform == 'win32' \
     --hash=sha256:08695f5cb7ed6e0531a20572697297273c47b8cae5a63ffc6d6ed5c201be6e44 \
     --hash=sha256:4f1d9991f5acc0ca119f9d443620b77f9d6b33703e51011c16baf57afb285fc6
     # via
-    #   -c dev_tools/requirements/max_compat/dev.env.txt
     #   pytest
     #   tqdm
 contourpy==1.3.2 \
@@ -242,9 +228,7 @@ contourpy==1.3.2 \
     --hash=sha256:f26b383144cf2d2c29f01a1e8170f50dacf0eac02d64139dcd709a8ac4eb3cfe \
     --hash=sha256:f939a054192ddc596e031e50bb13b657ce318cf13d264f095ce9db7dc6ae81c0 \
     --hash=sha256:fd93cc7f3139b6dd7aab2f26a90dde0aa9fc264dbf70f6740d498a70b860b82c
-    # via
-    #   -c dev_tools/requirements/max_compat/dev.env.txt
-    #   matplotlib
+    # via matplotlib
 coverage==7.14.1 \
     --hash=sha256:0177614a0370f227888b4e436a7c55686d6a9f90eb1ade2b624ba685a1686e86 \
     --hash=sha256:01b7733daad0237daa01ef80fe2dfceffc911e6a17fa7b55d14aa8214eaaaecd \
@@ -352,45 +336,31 @@ coverage==7.14.1 \
     --hash=sha256:fad54e871165f6ec2f536063ac74c3104508a12963e64072ba44bd822de52b0c \
     --hash=sha256:fc459e5d73be2d6332fcfe8dbf3d8994671fe33c700f4565988ecfa511547253 \
     --hash=sha256:fd86572566fb40189a8260446158235159bc7a82dfbc87a3b39cf4fb57fcec1c
-    # via
-    #   -c dev_tools/requirements/max_compat/dev.env.txt
-    #   pytest-cov
+    # via pytest-cov
 cycler==0.12.1 \
     --hash=sha256:85cef7cff222d8644161529808465972e51340599459b8ac3ccbac5a854e0d30 \
     --hash=sha256:88bb128f02ba341da8ef447245a9e138fae777f6a23943da4540077d3601eb1c
-    # via
-    #   -c dev_tools/requirements/max_compat/dev.env.txt
-    #   matplotlib
+    # via matplotlib
 deprecation==2.1.0 \
     --hash=sha256:72b3bde64e5d778694b0cf68178aed03d15e15477116add3fb773e581f9518ff \
     --hash=sha256:a10811591210e1fb0e768a8c25517cabeabcba6f0bf96564f8ff45189f90b14a
-    # via
-    #   -c dev_tools/requirements/max_compat/dev.env.txt
-    #   -r dev_tools/requirements/deps/runtime.txt
+    # via -r dev_tools/requirements/deps/runtime.txt
 duet==0.2.9 \
     --hash=sha256:a16088b68b0faee8aee12cdf4d0a8af060ed958badb44f3e32f123f13f64119a \
     --hash=sha256:d6fa39582e6a3dce1096c47e5fbcbda648a633eed94a38943e68662afa2587f3
-    # via
-    #   -c dev_tools/requirements/max_compat/dev.env.txt
-    #   cirq-core
+    # via cirq-core
 exceptiongroup==1.3.1 ; python_full_version < '3.11' \
     --hash=sha256:8b412432c6055b0b7d14c310000ae93352ed6754f70fa8f7c34141f91c4e3219 \
     --hash=sha256:a7a39a3bd276781e98394987d3a5701d0c4edffb633bb7a5144577f82c773598
-    # via
-    #   -c dev_tools/requirements/max_compat/dev.env.txt
-    #   pytest
+    # via pytest
 execnet==2.1.2 \
     --hash=sha256:63d83bfdd9a23e35b9c6a3261412324f964c2ec8dcd8d3c6916ee9373e0befcd \
     --hash=sha256:67fba928dd5a544b783f6056f449e5e3931a5c378b128bc18501f7ea79e296ec
-    # via
-    #   -c dev_tools/requirements/max_compat/dev.env.txt
-    #   pytest-xdist
+    # via pytest-xdist
 fastjsonschema==2.21.2 \
     --hash=sha256:1c797122d0a86c5cace2e54bf4e819c36223b552017172f32c5c024a6b77e463 \
     --hash=sha256:b1eb43748041c880796cd077f1a07c3d94e93ae84bba5ed36800a33554ae05de
-    # via
-    #   -c dev_tools/requirements/max_compat/dev.env.txt
-    #   nbformat
+    # via nbformat
 fonttools==4.63.0 \
     --hash=sha256:032038247a96c1690f9f31e377c389383c902531b085aa4e4dabd6f57f870e69 \
     --hash=sha256:063e08bd17bd5a90127a14123de0d6a952dbc847695fd98b63c043d58057f90c \
@@ -442,9 +412,7 @@ fonttools==4.63.0 \
     --hash=sha256:ee08ebfa58f6e1aeff5697ab9582105bb620008c1caafb681e4c557e7483027b \
     --hash=sha256:ef3048ef05dbb552b89817713d9cac912e00d0fde4a3105c00d29e52e10c89af \
     --hash=sha256:fd1e3094f42d806d3d7c79162fc59e5910fcbe3a7360c385b8da969bc4493745
-    # via
-    #   -c dev_tools/requirements/max_compat/dev.env.txt
-    #   matplotlib
+    # via matplotlib
 h5py==3.16.0 \
     --hash=sha256:099f2525c9dcf28de366970a5fb34879aab20491589fa89ce2863a84218bb524 \
     --hash=sha256:0f456f556e4e2cebeebd9d66adf8dc321770a42593494a0b6f0af54a7567b242 \
@@ -494,45 +462,31 @@ h5py==3.16.0 \
     --hash=sha256:fb1720028d99040792bb2fb31facb8da44a6f29df7697e0b84f0d79aff2e9bd3 \
     --hash=sha256:ff24039e2573297787c3063df64b60aab0591980ac898329a08b0320e0cf2527 \
     --hash=sha256:ffbab2fedd6581f6aa31cf1639ca2cb86e02779de525667892ebf4cc9fd26434
-    # via
-    #   -c dev_tools/requirements/max_compat/dev.env.txt
-    #   -r dev_tools/requirements/deps/runtime.txt
+    # via -r dev_tools/requirements/deps/runtime.txt
 idna==3.17 \
     --hash=sha256:466e48829084efe2548012b855df21540b96f2e20e51bd124c851536556a592c \
     --hash=sha256:5eb0cb53bc467c12eadcf6de83163ad8527cec9416f44b9b61b19caedad2b87f
-    # via
-    #   -c dev_tools/requirements/max_compat/dev.env.txt
-    #   requests
+    # via requests
 iniconfig==2.3.0 \
     --hash=sha256:c76315c77db068650d49c5b56314774a7804df16fee4402c1f19d6d15d8c4730 \
     --hash=sha256:f631c04d2c48c52b84d0d0549c99ff3859c98df65b3101406327ecc7d53fbf12
-    # via
-    #   -c dev_tools/requirements/max_compat/dev.env.txt
-    #   pytest
+    # via pytest
 jinja2==3.1.6 \
     --hash=sha256:0137fb05990d35f1275a587e9aee6d56da821fc83491a0fb838183be43f66d6d \
     --hash=sha256:85ece4451f492d0c13c5dd7c13a64681a86afae63a5f347908daf103ce6d2f67
-    # via
-    #   -c dev_tools/requirements/max_compat/dev.env.txt
-    #   tensorflow-docs
+    # via tensorflow-docs
 jsonschema==4.26.0 \
     --hash=sha256:0c26707e2efad8aa1bfc5b7ce170f3fccc2e4918ff85989ba9ffa9facb2be326 \
     --hash=sha256:d489f15263b8d200f8387e64b4c3a75f06629559fb73deb8fdfb525f2dab50ce
-    # via
-    #   -c dev_tools/requirements/max_compat/dev.env.txt
-    #   nbformat
+    # via nbformat
 jsonschema-specifications==2025.9.1 \
     --hash=sha256:98802fee3a11ee76ecaca44429fda8a41bff98b00a0f2838151b113f210cc6fe \
     --hash=sha256:b540987f239e745613c7a9176f3edb72b832a4ac465cf02712288397832b5e8d
-    # via
-    #   -c dev_tools/requirements/max_compat/dev.env.txt
-    #   jsonschema
+    # via jsonschema
 jupyter-core==5.9.1 \
     --hash=sha256:4d09aaff303b9566c3ce657f580bd089ff5c91f5f89cf7d8846c3cdf465b5508 \
     --hash=sha256:ebf87fdc6073d142e114c72c9e29a9d7ca03fad818c5d300ce2adc1fb0743407
-    # via
-    #   -c dev_tools/requirements/max_compat/dev.env.txt
-    #   nbformat
+    # via nbformat
 kiwisolver==1.5.0 \
     --hash=sha256:012b1eb16e28718fa782b5e61dc6f2da1f0792ca73bd05d54de6cb9561665fc9 \
     --hash=sha256:01808c6d15f4c3e8559595d6d1fe6411c68e4a3822b4b9972b44473b24f4e679 \
@@ -651,9 +605,7 @@ kiwisolver==1.5.0 \
     --hash=sha256:fc4d3f1fb9ca0ae9f97b095963bc6326f1dbfd3779d6679a1e016b9baaa153d3 \
     --hash=sha256:fd40bb9cd0891c4c3cb1ddf83f8bbfa15731a248fdc8162669405451e2724b09 \
     --hash=sha256:ff710414307fefa903e0d9bdf300972f892c23477829f49504e59834f4195398
-    # via
-    #   -c dev_tools/requirements/max_compat/dev.env.txt
-    #   matplotlib
+    # via matplotlib
 markupsafe==3.0.3 \
     --hash=sha256:0303439a41979d9e74d18ff5e2dd8c43ed6c6001fd40e5bf2e43f7bd9bbc523f \
     --hash=sha256:068f375c472b3e7acbe2d5318dea141359e6900156b5b2ba06a30b169086b91a \
@@ -744,9 +696,7 @@ markupsafe==3.0.3 \
     --hash=sha256:f71a396b3bf33ecaa1626c255855702aca4d3d9fea5e051b41ac59a9c1c41edc \
     --hash=sha256:f9e130248f4462aaa8e2552d547f36ddadbeaa573879158d721bbd33dfe4743a \
     --hash=sha256:fed51ac40f757d41b7c48425901843666a6677e3e8eb0abcff09e4ba6e664f50
-    # via
-    #   -c dev_tools/requirements/max_compat/dev.env.txt
-    #   jinja2
+    # via jinja2
 matplotlib==3.10.9 \
     --hash=sha256:09218df8a93712bd6ea133e83a153c755448cf7868316c531cffcc43f69d1cc9 \
     --hash=sha256:10cc5ce06d10231c36f40e875f3c7e8050362a4ee8f0ee5d29a6b3277d57bb42 \
@@ -803,27 +753,21 @@ matplotlib==3.10.9 \
     --hash=sha256:f4399f64b3e94cd500195490972ae1ee81170df1636fa15364d157d5bdd7b921 \
     --hash=sha256:f76e640a5268850bfda54b5131b1b1941cc685e42c5fa98ed9f2d64038308cba \
     --hash=sha256:fd66508e8c6877d98e586654b608a0456db8d7e8a546eb1e2600efd957302358
-    # via
-    #   -c dev_tools/requirements/max_compat/dev.env.txt
-    #   cirq-core
+    # via cirq-core
 mpmath==1.3.0 \
     --hash=sha256:7a28eb2a9774d00c7bc92411c19a89209d5da7c4c9a9e227be8330a23a25b91f \
     --hash=sha256:a0b2b9fe80bbcd81a6647ff13108738cfb482d481d826cc0e02f5b35e5c88d2c
-    # via
-    #   -c dev_tools/requirements/max_compat/dev.env.txt
-    #   sympy
+    # via sympy
 nbformat==5.10.4 \
     --hash=sha256:322168b14f937a5d11362988ecac2a4952d3d8e3a2cbeb2319584631226d5b3a \
     --hash=sha256:3b48d6c8fbca4b299bf3982ea7db1af21580e4fec269ad087b9e81588891200b
     # via
-    #   -c dev_tools/requirements/max_compat/dev.env.txt
     #   -r dev_tools/requirements/deps/pytest.txt
     #   tensorflow-docs
 networkx==3.4.2 \
     --hash=sha256:307c3669428c5362aab27c8a1260aa8f47c4e91d3891f48be0141738d8d053e1 \
     --hash=sha256:df5d4365b724cf81b8c6a7312509d0c22386097011ad1abe274afd5e9d3bbc5f
     # via
-    #   -c dev_tools/requirements/max_compat/dev.env.txt
     #   -r dev_tools/requirements/deps/runtime.txt
     #   cirq-core
 numpy==1.26.4 \
@@ -864,7 +808,6 @@ numpy==1.26.4 \
     --hash=sha256:f870204a840a60da0b12273ef34f7051e98c3b5961b61b0c2c1be6dfd64fbcd3 \
     --hash=sha256:ffa75af20b44f8dba823498024771d5ac50620e6915abac414251bd971b4529f
     # via
-    #   -c dev_tools/requirements/max_compat/dev.env.txt
     #   -r dev_tools/requirements/deps/runtime.txt
     #   cirq-core
     #   contourpy
@@ -876,7 +819,6 @@ packaging==26.2 \
     --hash=sha256:5fc45236b9446107ff2415ce77c807cee2862cb6fac22b8a73826d0693b0980e \
     --hash=sha256:ff452ff5a3e828ce110190feff1178bb1f2ea2281fa2075aadb987c2fb221661
     # via
-    #   -c dev_tools/requirements/max_compat/dev.env.txt
     #   deprecation
     #   matplotlib
     #   pytest
@@ -936,9 +878,7 @@ pandas==2.3.3 \
     --hash=sha256:ee67acbbf05014ea6c763beb097e03cd629961c8a632075eeb34247120abcb4b \
     --hash=sha256:f086f6fe114e19d92014a1966f43a3e62285109afe874f067f5abbdcbb10e59c \
     --hash=sha256:f8bfc0e12dc78f777f323f55c58649591b2cd0c43534e8355c51d3fede5f4dee
-    # via
-    #   -c dev_tools/requirements/max_compat/dev.env.txt
-    #   cirq-core
+    # via cirq-core
 pillow==12.2.0 \
     --hash=sha256:00a2865911330191c0b818c59103b58a5e697cae67042366970a6b6f1b20b7f9 \
     --hash=sha256:01afa7cf67f74f09523699b4e88c73fb55c13346d212a59a2db1f86b0a63e8c5 \
@@ -1031,20 +971,15 @@ pillow==12.2.0 \
     --hash=sha256:f490f9368b6fc026f021db16d7ec2fbf7d89e2edb42e8ec09d2c60505f5729c7 \
     --hash=sha256:fb043ee2f06b41473269765c2feae53fc2e2fbf96e5e22ca94fb5ad677856f06 \
     --hash=sha256:fc3d34d4a8fbec3e88a79b92e5465e0f9b842b628675850d860b8bd300b159f5
-    # via
-    #   -c dev_tools/requirements/max_compat/dev.env.txt
-    #   matplotlib
+    # via matplotlib
 platformdirs==4.10.0 \
     --hash=sha256:31e761a6a0ca04faf7353ea759bdba55652be214725111e5aac52dfa29d4bef7 \
     --hash=sha256:fb516cdb12eb0d857d0cd85a7c57cea4d060bee4578d6cf5a14dfdf8cbf8784a
-    # via
-    #   -c dev_tools/requirements/max_compat/dev.env.txt
-    #   jupyter-core
+    # via jupyter-core
 pluggy==1.6.0 \
     --hash=sha256:7dcc130b76258d33b90f61b658791dede3486c3e6bfb003ee5c9bfb396dd22f3 \
     --hash=sha256:e920276dd6813095e9377c0bc5566d94c932c33b27a3e3945d8389c374dd4746
     # via
-    #   -c dev_tools/requirements/max_compat/dev.env.txt
     #   pytest
     #   pytest-cov
 protobuf==7.35.0 \
@@ -1056,32 +991,23 @@ protobuf==7.35.0 \
     --hash=sha256:c13f325cf242bad135c350629eeb5d54b24228eb472fb3e2e9ebbd4c5dc20ca0 \
     --hash=sha256:f05bcadf9a2a6b8dda047007075135fb7d08c73d9177aabc067e1be46881a201 \
     --hash=sha256:fcbe42a4ac09d3ec9c987ddfcd956afd0b15f1ff613bd8371bde9405ffd5c8e5
-    # via
-    #   -c dev_tools/requirements/max_compat/dev.env.txt
-    #   tensorflow-docs
+    # via tensorflow-docs
 pubchempy==1.0.5 \
     --hash=sha256:08f0b2a82a5caa5d61e14935d655da554602d7b5686fe661ab584c882ffff623 \
     --hash=sha256:e936cfed31fa194042ad463be3c803dde5b12ef2f795caf336e3114127c34fa0
-    # via
-    #   -c dev_tools/requirements/max_compat/dev.env.txt
-    #   -r dev_tools/requirements/deps/runtime.txt
+    # via -r dev_tools/requirements/deps/runtime.txt
 pygments==2.20.0 \
     --hash=sha256:6757cd03768053ff99f3039c1a36d6c0aa0b263438fcab17520b30a303a82b5f \
     --hash=sha256:81a9e26dd42fd28a23a2d169d86d7ac03b46e2f8b59ed4698fb4785f946d0176
-    # via
-    #   -c dev_tools/requirements/max_compat/dev.env.txt
-    #   pytest
+    # via pytest
 pyparsing==3.3.2 \
     --hash=sha256:850ba148bd908d7e2411587e247a1e4f0327839c40e2e5e6d05a007ecc69911d \
     --hash=sha256:c777f4d763f140633dcb6d8a3eda953bf7a214dc4eff598413c070bcdc117cbc
-    # via
-    #   -c dev_tools/requirements/max_compat/dev.env.txt
-    #   matplotlib
+    # via matplotlib
 pytest==9.0.3 \
     --hash=sha256:2c5efc453d45394fdd706ade797c0a81091eccd1d6e4bccfcd476e2b8e0ab5d9 \
     --hash=sha256:b86ada508af81d19edeb213c681b1d48246c1a91d304c6c81a427674c17eb91c
     # via
-    #   -c dev_tools/requirements/max_compat/dev.env.txt
     #   -r dev_tools/requirements/deps/pytest.txt
     #   pytest-asyncio
     #   pytest-cov
@@ -1091,46 +1017,33 @@ pytest==9.0.3 \
 pytest-asyncio==1.4.0 \
     --hash=sha256:933ca923a23075a87fb7070c0ec272a6848489824d887c85c812670932835aa1 \
     --hash=sha256:c6c0d2259945122819f171a32ecea2c349ead889ee28176caaf492143424be42
-    # via
-    #   -c dev_tools/requirements/max_compat/dev.env.txt
-    #   -r dev_tools/requirements/deps/pytest.txt
+    # via -r dev_tools/requirements/deps/pytest.txt
 pytest-cov==7.1.0 \
     --hash=sha256:30674f2b5f6351aa09702a9c8c364f6a01c27aae0c1366ae8016160d1efc56b2 \
     --hash=sha256:a0461110b7865f9a271aa1b51e516c9a95de9d696734a2f71e3e78f46e1d4678
-    # via
-    #   -c dev_tools/requirements/max_compat/dev.env.txt
-    #   -r dev_tools/requirements/deps/pytest.txt
+    # via -r dev_tools/requirements/deps/pytest.txt
 pytest-randomly==4.1.0 \
     --hash=sha256:47f1d9746c3bc3efabd53ae1ebfb8bb385cf3d4df4b505b6d58d9c97a3dfe70f \
     --hash=sha256:f55e89e53367b090c0c053697d7f9d77595543d0e0516c93978b50c0f6b252f9
-    # via
-    #   -c dev_tools/requirements/max_compat/dev.env.txt
-    #   -r dev_tools/requirements/deps/pytest.txt
+    # via -r dev_tools/requirements/deps/pytest.txt
 pytest-retry==1.7.0 \
     --hash=sha256:a2dac85b79a4e2375943f1429479c65beb6c69553e7dae6b8332be47a60954f4 \
     --hash=sha256:f8d52339f01e949df47c11ba9ee8d5b362f5824dff580d3870ec9ae0057df80f
-    # via
-    #   -c dev_tools/requirements/max_compat/dev.env.txt
-    #   -r dev_tools/requirements/deps/pytest.txt
+    # via -r dev_tools/requirements/deps/pytest.txt
 pytest-xdist==3.8.0 \
     --hash=sha256:202ca578cfeb7370784a8c33d6d05bc6e13b4f25b5053c30a152269fd10f0b88 \
     --hash=sha256:7e578125ec9bc6050861aa93f2d59f1d8d085595d6551c2c90b6f4fad8d3a9f1
-    # via
-    #   -c dev_tools/requirements/max_compat/dev.env.txt
-    #   -r dev_tools/requirements/deps/pytest.txt
+    # via -r dev_tools/requirements/deps/pytest.txt
 python-dateutil==2.9.0.post0 \
     --hash=sha256:37dd54208da7e1cd875388217d5e00ebd4179249f90fb72437e91a35459a0ad3 \
     --hash=sha256:a8b2bc7bffae282281c8140a97d3aa9c14da0b136dfe83f850eea9a5f7470427
     # via
-    #   -c dev_tools/requirements/max_compat/dev.env.txt
     #   matplotlib
     #   pandas
 pytz==2026.2 \
     --hash=sha256:04156e608bee23d3792fd45c94ae47fae1036688e75032eea2e3bf0323d1f126 \
     --hash=sha256:0e60b47b29f21574376f218fe21abc009894a2321ea16c6754f3cad6eb7cdd6a
-    # via
-    #   -c dev_tools/requirements/max_compat/dev.env.txt
-    #   pandas
+    # via pandas
 pyyaml==6.0.3 \
     --hash=sha256:00c4bdeba853cc34e7dd471f16b4114f4162dc03e6b7afcc2128711f0eca823c \
     --hash=sha256:0150219816b6a1fa26fb4699fb7daa9caf09eb1999f3b70fb6e786805e80375a \
@@ -1205,22 +1118,17 @@ pyyaml==6.0.3 \
     --hash=sha256:f7057c9a337546edc7973c0d3ba84ddcdf0daa14533c2065749c9075001090e6 \
     --hash=sha256:fa160448684b4e94d80416c0fa4aac48967a969efe22931448d853ada8baf926 \
     --hash=sha256:fc09d0aa354569bc501d4e787133afc08552722d3ab34836a80547331bb5d4a0
-    # via
-    #   -c dev_tools/requirements/max_compat/dev.env.txt
-    #   tensorflow-docs
+    # via tensorflow-docs
 referencing==0.37.0 \
     --hash=sha256:381329a9f99628c9069361716891d34ad94af76e461dcb0335825aecc7692231 \
     --hash=sha256:44aefc3142c5b842538163acb373e24cce6632bd54bdb01b21ad5863489f50d8
     # via
-    #   -c dev_tools/requirements/max_compat/dev.env.txt
     #   jsonschema
     #   jsonschema-specifications
 requests==2.34.2 \
     --hash=sha256:2a0d60c172f83ac6ab31e4554906c0f3b3588d37b5cb939b1c061f4907e278e0 \
     --hash=sha256:f288924cae4e29463698d6d60bc6a4da69c89185ad1e0bcc4104f584e960b9ed
-    # via
-    #   -c dev_tools/requirements/max_compat/dev.env.txt
-    #   -r dev_tools/requirements/deps/runtime.txt
+    # via -r dev_tools/requirements/deps/runtime.txt
 rpds-py==0.30.0 \
     --hash=sha256:07ae8a593e1c3c6b82ca3292efbe73c30b61332fd612e05abee07c79359f292f \
     --hash=sha256:0a59119fc6e3f460315fe9d08149f8102aa322299deaa5cab5b40092345c2136 \
@@ -1338,7 +1246,6 @@ rpds-py==0.30.0 \
     --hash=sha256:f8d1736cfb49381ba528cd5baa46f82fdc65c06e843dab24dd70b63d09121b3f \
     --hash=sha256:fe5fa731a1fa8a0a56b0977413f8cacac1768dad38d16b3a296712709476fbd5
     # via
-    #   -c dev_tools/requirements/max_compat/dev.env.txt
     #   jsonschema
     #   referencing
 scipy==1.15.3 \
@@ -1389,33 +1296,29 @@ scipy==1.15.3 \
     --hash=sha256:ed7284b21a7a0c8f1b6e5977ac05396c0d008b89e05498c8b7e8f4a1423bba0e \
     --hash=sha256:f77f853d584e72e874d87357ad70f44b437331507d1c311457bed8ed2b956126
     # via
-    #   -c dev_tools/requirements/max_compat/dev.env.txt
     #   -r dev_tools/requirements/deps/runtime.txt
     #   cirq-core
 six==1.17.0 \
     --hash=sha256:4721f391ed90541fddacab5acf947aa0d3dc7d27b2e1e8eda2be8970586c3274 \
     --hash=sha256:ff70335d468e7eb6ec65b95b99d3a2836546063f63acc5171de367e834932a81
-    # via
-    #   -c dev_tools/requirements/max_compat/dev.env.txt
-    #   python-dateutil
+    # via python-dateutil
 sortedcontainers==2.4.0 \
     --hash=sha256:25caa5a06cc30b6b83d11423433f65d1f9d76c4c6a0c90e3379eaa43b9bfdb88 \
     --hash=sha256:a163dcaede0f1c021485e957a39245190e74249897e2ae4b2aa38595db237ee0
-    # via
-    #   -c dev_tools/requirements/max_compat/dev.env.txt
-    #   cirq-core
+    # via cirq-core
 sympy==1.14.0 \
     --hash=sha256:d3d3fe8df1e5a0b42f0e7bdf50541697dbe7d23746e894990c030e2b05e72517 \
     --hash=sha256:e091cc3e99d2141a0ba2847328f5479b05d94a6635cb96148ccb3f34671bd8f5
     # via
-    #   -c dev_tools/requirements/max_compat/dev.env.txt
     #   -r dev_tools/requirements/deps/runtime.txt
     #   cirq-core
 tensorflow-docs==2025.2.19.33219 \
     --hash=sha256:b52682f3739110ce804af701f9ab5ac1efe07760109a5b5640769851d7d14b19
-    # via
-    #   -c dev_tools/requirements/max_compat/dev.env.txt
-    #   -r dev_tools/requirements/deps/pytest.txt
+    # via -r dev_tools/requirements/deps/pytest.txt
+threadpoolctl==3.6.0 \
+    --hash=sha256:43a0b8fd5a2928500110039e43a5eed8480b918967083ea48dc3ab9f13c4a7fb \
+    --hash=sha256:8ab8b4aa3491d812b623328249fab5302a68d2d71745c8a4c719a2fcaba9f44e
+    # via -r dev_tools/requirements/deps/pytest.txt
 tomli==2.4.1 ; python_full_version <= '3.11' \
     --hash=sha256:01f520d4f53ef97964a240a035ec2a869fe1a37dde002b57ebc4417a27ccd853 \
     --hash=sha256:0d85819802132122da43cb86656f8d1f8c6587d54ae7dcaf30e90533028b49fe \
@@ -1465,27 +1368,22 @@ tomli==2.4.1 ; python_full_version <= '3.11' \
     --hash=sha256:ff18e6a727ee0ab0388507b89d1bc6a22b138d1e2fa56d1ad494586d61d2eae9 \
     --hash=sha256:ff2983983d34813c1aeb0fa89091e76c3a22889ee83ab27c5eeb45100560c049
     # via
-    #   -c dev_tools/requirements/max_compat/dev.env.txt
     #   coverage
     #   pytest
 tqdm==4.67.3 \
     --hash=sha256:7d825f03f89244ef73f1d4ce193cb1774a8179fd96f31d7e1dcde62092b960bb \
     --hash=sha256:ee1e4c0e59148062281c49d80b25b67771a127c85fc9676d3be5f243206826bf
-    # via
-    #   -c dev_tools/requirements/max_compat/dev.env.txt
-    #   cirq-core
+    # via cirq-core
 traitlets==5.15.0 \
     --hash=sha256:4fead733f81cf1c4c938e06f8ca4633896833c9d89eff878159457f4d4392971 \
     --hash=sha256:fb36a18867a6803deab09f3c5e0fa81bb7b26a5c9e82501c9933f759166eff40
     # via
-    #   -c dev_tools/requirements/max_compat/dev.env.txt
     #   jupyter-core
     #   nbformat
 typing-extensions==4.15.0 \
     --hash=sha256:0cea48d173cc12fa28ecabc3b837ea3cf6f38c6d1136f85cbaaf598984861466 \
     --hash=sha256:f0fa19c6845758ab08074a0cfa8b7aecb71c999ca73d62883bc25cc018c4e548
     # via
-    #   -c dev_tools/requirements/max_compat/dev.env.txt
     #   cirq-core
     #   exceptiongroup
     #   pytest-asyncio
@@ -1493,12 +1391,8 @@ typing-extensions==4.15.0 \
 tzdata==2026.2 \
     --hash=sha256:9173fde7d80d9018e02a662e168e5a2d04f87c41ea174b139fbef642eda62d10 \
     --hash=sha256:bbe9af844f658da81a5f95019480da3a89415801f6cc966806612cc7169bffe7
-    # via
-    #   -c dev_tools/requirements/max_compat/dev.env.txt
-    #   pandas
+    # via pandas
 urllib3==2.7.0 \
     --hash=sha256:231e0ec3b63ceb14667c67be60f2f2c40a518cb38b03af60abc813da26505f4c \
     --hash=sha256:9fb4c81ebbb1ce9531cce37674bbc6f1360472bc18ca9a553ede278ef7276897
-    # via
-    #   -c dev_tools/requirements/max_compat/dev.env.txt
-    #   requests
+    # via requests

From 43ec834cbad36cd787c9717b395be40ee7ddfaae Mon Sep 17 00:00:00 2001
From: mhucka <mhucka@google.com>
Date: Fri, 10 Jul 2026 04:04:18 +0000
Subject: [PATCH 31/42] Use self.qubit_operator

Per review comment by Adam.
---
 src/openfermion/linalg/linear_qubit_operator_test.py | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/openfermion/linalg/linear_qubit_operator_test.py b/src/openfermion/linalg/linear_qubit_operator_test.py
index cd9f7d005..898b85746 100644
--- a/src/openfermion/linalg/linear_qubit_operator_test.py
+++ b/src/openfermion/linalg/linear_qubit_operator_test.py
@@ -264,10 +264,9 @@ def test_closed_workers_not_reused(self):
 
     def test_matvec_single_process(self):
         """Tests that when processes is 1, it computes correctly and doesn't crash."""
-        qubit_operator = QubitOperator('Z3') + QubitOperator('Y0') + QubitOperator('X1')
         options = LinearQubitOperatorOptions(processes=1)
         parallel_qubit_op = ParallelLinearQubitOperator(
-            qubit_operator, self.n_qubits, options=options
+            self.qubit_operator, self.n_qubits, options=options
         )
         self.assertTrue(numpy.allclose(parallel_qubit_op * self.vec, self.expected_matvec))
 

From b49816ceafe8b9b52ea4978b64d388107ae56532 Mon Sep 17 00:00:00 2001
From: mhucka <mhucka@google.com>
Date: Fri, 10 Jul 2026 17:39:05 +0000
Subject: [PATCH 32/42] Be more DRY

---
 check/pylint-changed-files | 15 ++++++++-------
 1 file changed, 8 insertions(+), 7 deletions(-)

diff --git a/check/pylint-changed-files b/check/pylint-changed-files
index c3248ad31..75c83bfdf 100755
--- a/check/pylint-changed-files
+++ b/check/pylint-changed-files
@@ -59,18 +59,19 @@ for arg in "$@"; do
 done
 
 if [[ -z "${rev}" ]]; then
-    if [[ "$(git cat-file -t "upstream/main" 2> /dev/null)" == "commit" ]]; then
-        rev=upstream/main
-    elif [[ "$(git cat-file -t "origin/main" 2> /dev/null)" == "commit" ]]; then
-        rev=origin/main
-    elif [[ "$(git cat-file -t "main" 2> /dev/null)" == "commit" ]]; then
-        rev=main
-    else
+    for candidate in upstream/main origin/main main; do
+        if [[ "$(git cat-file -t "${candidate}" 2>/dev/null)" == "commit" ]]; then
+            rev="${candidate}"
+            break
+        fi
+    done
+    if [[ -z "${rev}" ]]; then
         echo -e "\033[31mNo default revision found to compare against. \
 Please specify a base revision (e.g. 'origin/main' or 'HEAD~1') as an argument.\033[0m" >&2
         exit 1
     fi
 fi
+
 base=$(git merge-base "${rev}" HEAD)
 if [[ "$(git rev-parse "${rev}")" == "${base}" ]]; then
     echo -e "Comparing against revision '${rev}'." >&2

From 09ec54422fbac2b5a96eaa3f50de207167fe4acd Mon Sep 17 00:00:00 2001
From: mhucka <mhucka@google.com>
Date: Fri, 10 Jul 2026 17:41:19 +0000
Subject: [PATCH 33/42] Be more DRY

---
 check/pytest-and-incremental-coverage | 15 ++++++++-------
 1 file changed, 8 insertions(+), 7 deletions(-)

diff --git a/check/pytest-and-incremental-coverage b/check/pytest-and-incremental-coverage
index 77c0a5e23..a716ffa82 100755
--- a/check/pytest-and-incremental-coverage
+++ b/check/pytest-and-incremental-coverage
@@ -55,18 +55,19 @@ for arg in "$@"; do
 done
 
 if [[ -z "${rev}" ]]; then
-    if [[ "$(git cat-file -t upstream/main 2> /dev/null)" == "commit" ]]; then
-        rev=upstream/main
-    elif [[ "$(git cat-file -t origin/main 2> /dev/null)" == "commit" ]]; then
-        rev=origin/main
-    elif [[ "$(git cat-file -t main 2> /dev/null)" == "commit" ]]; then
-        rev=main
-    else
+    for candidate in upstream/main origin/main main; do
+        if [[ "$(git cat-file -t "${candidate}" 2>/dev/null)" == "commit" ]]; then
+            rev="${candidate}"
+            break
+        fi
+    done
+    if [[ -z "${rev}" ]]; then
         echo -e "\033[31mNo default revision found to compare against. \
 Please specify a base revision (e.g. 'origin/main' or 'HEAD~1') as an argument.\033[0m" >&2
         exit 1
     fi
 fi
+
 base="$(git merge-base "${rev}" HEAD)"
 if [[ "$(git rev-parse "${rev}")" == "${base}" ]]; then
     echo -e "Comparing against revision '${rev}'." >&2

From e682c5ef943bd04a5d480e4d3207506ae51c6b80 Mon Sep 17 00:00:00 2001
From: mhucka <mhucka@google.com>
Date: Fri, 10 Jul 2026 17:45:38 +0000
Subject: [PATCH 34/42] Fix typo

---
 conftest.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/conftest.py b/conftest.py
index 31caabe2c..080bcba9d 100644
--- a/conftest.py
+++ b/conftest.py
@@ -49,7 +49,7 @@ def set_threadpool_limits():
     """Limit number of threads to prevent oversubscription with pytest-xdist.
 
     This only has an effect if the Python threadpoolctl package is installed,
-    and it only influences parallellism in some numerical libraries used in
+    and it only influences parallelism in some numerical libraries used in
     packages such as NumPy.
     """
     try:

From e1c0cbc3197ae2199b3fdd0e697dbb0b72aea494 Mon Sep 17 00:00:00 2001
From: mhucka <mhucka@google.com>
Date: Sat, 11 Jul 2026 02:14:43 +0000
Subject: [PATCH 35/42] Do not set pylint "jobs" in `.pylintrc`

---
 .pylintrc | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/.pylintrc b/.pylintrc
index a77a7e2b0..39450d38f 100644
--- a/.pylintrc
+++ b/.pylintrc
@@ -90,7 +90,7 @@ ignored-modules=
 # Use multiple processes to speed up Pylint. Specifying 0 will auto-detect the
 # number of processors available to use, and will cap the count on Windows to
 # avoid hangs.
-jobs=0
+# jobs=0
 
 # Control the amount of potential inferred values when inferring a single
 # object. This can help the performance when dealing with large functions or

From 2cb9c1423fd2083801f8f28329bf60996be62a2e Mon Sep 17 00:00:00 2001
From: mhucka <mhucka@google.com>
Date: Sat, 11 Jul 2026 02:54:05 +0000
Subject: [PATCH 36/42] Make check/pylint print something when it's successful

---
 check/pylint | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/check/pylint b/check/pylint
index 9239f8c1d..16c2f6d07 100755
--- a/check/pylint
+++ b/check/pylint
@@ -24,4 +24,4 @@
 cd "$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )" || exit 1
 cd "$(git rev-parse --show-toplevel)" || exit 1
 
-pylint "$@" src dev_tools
+pylint "$@" src dev_tools && echo "Pylint completed successfully."

From 74d65ceecb386774d4adca571e566d2347ea1224 Mon Sep 17 00:00:00 2001
From: mhucka <mhucka@google.com>
Date: Sat, 11 Jul 2026 02:55:19 +0000
Subject: [PATCH 37/42] Add psutil to pytest dependencies

---
 dev_tools/requirements/deps/pytest.txt | 1 +
 1 file changed, 1 insertion(+)

diff --git a/dev_tools/requirements/deps/pytest.txt b/dev_tools/requirements/deps/pytest.txt
index c56b085c8..552dcefc0 100644
--- a/dev_tools/requirements/deps/pytest.txt
+++ b/dev_tools/requirements/deps/pytest.txt
@@ -6,5 +6,6 @@ pytest-retry
 pytest-xdist
 
 nbformat
+psutil
 tensorflow-docs
 threadpoolctl

From a9bbf02fb41bc4f33e0494d43e862b131a16c099 Mon Sep 17 00:00:00 2001
From: mhucka <mhucka@google.com>
Date: Sat, 11 Jul 2026 02:56:26 +0000
Subject: [PATCH 38/42] Add parallelism option to mypy

---
 check/all | 14 +++++++++++---
 1 file changed, 11 insertions(+), 3 deletions(-)

diff --git a/check/all b/check/all
index 1111a4d2a..bc1341613 100755
--- a/check/all
+++ b/check/all
@@ -100,15 +100,23 @@ done
 declare -a errors=()
 declare -a pylint_j=()
 declare -a pytest_n=()
+declare -a mypy_n=()
 
 function run() {
     echo "Running $*"
     "$@" || errors+=( "$* failed" )
 }
 
+# Count only the physical cores (usually fewer than logical cores). This leaves
+# some CPU resources for OpenFermion modules that use multiple processes.
+cpus=$(python3 -c 'import psutil; print(psutil.cpu_count(logical=False))')
+
 if [[ -z "${no_parallel}" ]]; then
-    pylint_j=("-j0")
-    pytest_n=("-n" "auto")
+    # Pylint & pytest can auto-detect the number of CPUs, but not mypy. To be
+    # consistent, this uses the same explicit number for all of them.
+    pylint_j=("-j" "${cpus}")
+    pytest_n=("-n" "${cpus}")
+    mypy_n=("-n" "${cpus}")
 fi
 
 if [[ -n "${only_changed}" ]]; then
@@ -118,7 +126,7 @@ else
     run check/format-incremental "${rev[@]}" "${apply_arg[@]}" --all
     run check/pylint "${pylint_j[@]}" "${rev[@]}"
 fi
-run check/mypy
+run check/mypy "${mypy_n[@]}"
 run check/pytest-and-incremental-coverage "${pytest_n[@]}" "${rev[@]}"
 run check/shellcheck
 run check/nbformat

From f329f9f2c655c23ce55bdc4bdbb1c8811b1b9cc0 Mon Sep 17 00:00:00 2001
From: mhucka <mhucka@google.com>
Date: Sat, 11 Jul 2026 02:56:48 +0000
Subject: [PATCH 39/42] Print a more noticeable "running ABC" message

---
 check/all | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/check/all b/check/all
index bc1341613..04946a011 100755
--- a/check/all
+++ b/check/all
@@ -103,7 +103,7 @@ declare -a pytest_n=()
 declare -a mypy_n=()
 
 function run() {
-    echo "Running $*"
+    echo "~~~~ Running $* ~~~~"
     "$@" || errors+=( "$* failed" )
 }
 

From a6fd00e446d1265a9a4ab06ee20a6d31c90cc380 Mon Sep 17 00:00:00 2001
From: mhucka <mhucka@google.com>
Date: Sat, 11 Jul 2026 02:58:40 +0000
Subject: [PATCH 40/42] Make check/shellcheck print something when it's
 successful

---
 check/shellcheck | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/check/shellcheck b/check/shellcheck
index 1c796506c..85be18a98 100755
--- a/check/shellcheck
+++ b/check/shellcheck
@@ -81,5 +81,6 @@ if (( opt_dry_run )); then
     printf '\\\n  %s ' "${our_shell_scripts[@]}"
     printf '\\\n;\n'
 else
-    shellcheck "${shellcheck_options[@]}" "${our_shell_scripts[@]}"
+    shellcheck "${shellcheck_options[@]}" "${our_shell_scripts[@]}" && \
+        echo "shellcheck completed successfully."
 fi

From 8e50d3ca71b3e3236543f6c66c46155647c691c4 Mon Sep 17 00:00:00 2001
From: mhucka <mhucka@google.com>
Date: Sat, 11 Jul 2026 03:01:09 +0000
Subject: [PATCH 41/42] Tell people about the `-j 0` option

---
 CONTRIBUTING.md | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index e6f67fe38..e4b603e49 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -263,9 +263,12 @@ for formatting code, and provide scripts to run them.
 *   To run the linter:
 
     ```shell
-    check/pylint-changed-files
+    check/pylint-changed-files -j 0
     ```
 
+    (The option `-j 0` tells pylint to use parallel processes; omit it if it causes problems on your
+    system.)
+
 ### Testing and test coverage
 
 When new functions, classes, and files are introduced, they should also have corresponding tests.

From 7f36f75934de08c77eda361f6b5bf9430aa0dc61 Mon Sep 17 00:00:00 2001
From: mhucka <mhucka@google.com>
Date: Sat, 11 Jul 2026 03:30:08 +0000
Subject: [PATCH 42/42] Regenerate requirements files after change to
 pytest.txt

---
 dev_tools/requirements/envs/dev.env.txt       | 23 +++++++++++++++++
 dev_tools/requirements/envs/pylint.env.txt    | 25 +++++++++++++++++++
 .../requirements/envs/pytest-extra.env.txt    | 25 +++++++++++++++++++
 dev_tools/requirements/envs/pytest.env.txt    | 25 +++++++++++++++++++
 .../max_compat/pytest-max-compat.env.txt      | 23 +++++++++++++++++
 5 files changed, 121 insertions(+)

diff --git a/dev_tools/requirements/envs/dev.env.txt b/dev_tools/requirements/envs/dev.env.txt
index b6abff1a0..f8dabf30e 100644
--- a/dev_tools/requirements/envs/dev.env.txt
+++ b/dev_tools/requirements/envs/dev.env.txt
@@ -1581,6 +1581,29 @@ protobuf==7.35.0 \
     --hash=sha256:f05bcadf9a2a6b8dda047007075135fb7d08c73d9177aabc067e1be46881a201 \
     --hash=sha256:fcbe42a4ac09d3ec9c987ddfcd956afd0b15f1ff613bd8371bde9405ffd5c8e5
     # via tensorflow-docs
+psutil==7.2.2 \
+    --hash=sha256:0746f5f8d406af344fd547f1c8daa5f5c33dbc293bb8d6a16d80b4bb88f59372 \
+    --hash=sha256:076a2d2f923fd4821644f5ba89f059523da90dc9014e85f8e45a5774ca5bc6f9 \
+    --hash=sha256:11fe5a4f613759764e79c65cf11ebdf26e33d6dd34336f8a337aa2996d71c841 \
+    --hash=sha256:1a571f2330c966c62aeda00dd24620425d4b0cc86881c89861fbc04549e5dc63 \
+    --hash=sha256:1a7b04c10f32cc88ab39cbf606e117fd74721c831c98a27dc04578deb0c16979 \
+    --hash=sha256:1fa4ecf83bcdf6e6c8f4449aff98eefb5d0604bf88cb883d7da3d8d2d909546a \
+    --hash=sha256:2edccc433cbfa046b980b0df0171cd25bcaeb3a68fe9022db0979e7aa74a826b \
+    --hash=sha256:7b6d09433a10592ce39b13d7be5a54fbac1d1228ed29abc880fb23df7cb694c9 \
+    --hash=sha256:8c233660f575a5a89e6d4cb65d9f938126312bca76d8fe087b947b3a1aaac9ee \
+    --hash=sha256:917e891983ca3c1887b4ef36447b1e0873e70c933afc831c6b6da078ba474312 \
+    --hash=sha256:ab486563df44c17f5173621c7b198955bd6b613fb87c71c161f827d3fb149a9b \
+    --hash=sha256:ae0aefdd8796a7737eccea863f80f81e468a1e4cf14d926bd9b6f5f2d5f90ca9 \
+    --hash=sha256:b0726cecd84f9474419d67252add4ac0cd9811b04d61123054b9fb6f57df6e9e \
+    --hash=sha256:b58fabe35e80b264a4e3bb23e6b96f9e45a3df7fb7eed419ac0e5947c61e47cc \
+    --hash=sha256:c7663d4e37f13e884d13994247449e9f8f574bc4655d509c3b95e9ec9e2b9dc1 \
+    --hash=sha256:e452c464a02e7dc7822a05d25db4cde564444a67e58539a00f929c51eddda0cf \
+    --hash=sha256:e78c8603dcd9a04c7364f1a3e670cea95d51ee865e4efb3556a3a63adef958ea \
+    --hash=sha256:eb7e81434c8d223ec4a219b5fc1c47d0417b12be7ea866e24fb5ad6e84b3d988 \
+    --hash=sha256:ed0cace939114f62738d808fdcecd4c869222507e266e574799e9c0faa17d486 \
+    --hash=sha256:eed63d3b4d62449571547b60578c5b2c4bcccc5387148db46e0c2313dad0ee00 \
+    --hash=sha256:fd04ef36b4a6d599bbdb225dd1d3f51e00105f6d48a28f006da7f9822f2606d8
+    # via -r dev_tools/requirements/deps/pytest.txt
 pubchempy==1.0.5 \
     --hash=sha256:08f0b2a82a5caa5d61e14935d655da554602d7b5686fe661ab584c882ffff623 \
     --hash=sha256:e936cfed31fa194042ad463be3c803dde5b12ef2f795caf336e3114127c34fa0
diff --git a/dev_tools/requirements/envs/pylint.env.txt b/dev_tools/requirements/envs/pylint.env.txt
index 906531b76..82a7bd938 100644
--- a/dev_tools/requirements/envs/pylint.env.txt
+++ b/dev_tools/requirements/envs/pylint.env.txt
@@ -1196,6 +1196,31 @@ protobuf==7.35.0 \
     # via
     #   -c dev_tools/requirements/envs/dev.env.txt
     #   tensorflow-docs
+psutil==7.2.2 \
+    --hash=sha256:0746f5f8d406af344fd547f1c8daa5f5c33dbc293bb8d6a16d80b4bb88f59372 \
+    --hash=sha256:076a2d2f923fd4821644f5ba89f059523da90dc9014e85f8e45a5774ca5bc6f9 \
+    --hash=sha256:11fe5a4f613759764e79c65cf11ebdf26e33d6dd34336f8a337aa2996d71c841 \
+    --hash=sha256:1a571f2330c966c62aeda00dd24620425d4b0cc86881c89861fbc04549e5dc63 \
+    --hash=sha256:1a7b04c10f32cc88ab39cbf606e117fd74721c831c98a27dc04578deb0c16979 \
+    --hash=sha256:1fa4ecf83bcdf6e6c8f4449aff98eefb5d0604bf88cb883d7da3d8d2d909546a \
+    --hash=sha256:2edccc433cbfa046b980b0df0171cd25bcaeb3a68fe9022db0979e7aa74a826b \
+    --hash=sha256:7b6d09433a10592ce39b13d7be5a54fbac1d1228ed29abc880fb23df7cb694c9 \
+    --hash=sha256:8c233660f575a5a89e6d4cb65d9f938126312bca76d8fe087b947b3a1aaac9ee \
+    --hash=sha256:917e891983ca3c1887b4ef36447b1e0873e70c933afc831c6b6da078ba474312 \
+    --hash=sha256:ab486563df44c17f5173621c7b198955bd6b613fb87c71c161f827d3fb149a9b \
+    --hash=sha256:ae0aefdd8796a7737eccea863f80f81e468a1e4cf14d926bd9b6f5f2d5f90ca9 \
+    --hash=sha256:b0726cecd84f9474419d67252add4ac0cd9811b04d61123054b9fb6f57df6e9e \
+    --hash=sha256:b58fabe35e80b264a4e3bb23e6b96f9e45a3df7fb7eed419ac0e5947c61e47cc \
+    --hash=sha256:c7663d4e37f13e884d13994247449e9f8f574bc4655d509c3b95e9ec9e2b9dc1 \
+    --hash=sha256:e452c464a02e7dc7822a05d25db4cde564444a67e58539a00f929c51eddda0cf \
+    --hash=sha256:e78c8603dcd9a04c7364f1a3e670cea95d51ee865e4efb3556a3a63adef958ea \
+    --hash=sha256:eb7e81434c8d223ec4a219b5fc1c47d0417b12be7ea866e24fb5ad6e84b3d988 \
+    --hash=sha256:ed0cace939114f62738d808fdcecd4c869222507e266e574799e9c0faa17d486 \
+    --hash=sha256:eed63d3b4d62449571547b60578c5b2c4bcccc5387148db46e0c2313dad0ee00 \
+    --hash=sha256:fd04ef36b4a6d599bbdb225dd1d3f51e00105f6d48a28f006da7f9822f2606d8
+    # via
+    #   -c dev_tools/requirements/envs/dev.env.txt
+    #   -r dev_tools/requirements/deps/pytest.txt
 pubchempy==1.0.5 \
     --hash=sha256:08f0b2a82a5caa5d61e14935d655da554602d7b5686fe661ab584c882ffff623 \
     --hash=sha256:e936cfed31fa194042ad463be3c803dde5b12ef2f795caf336e3114127c34fa0
diff --git a/dev_tools/requirements/envs/pytest-extra.env.txt b/dev_tools/requirements/envs/pytest-extra.env.txt
index 147da67ee..e6568c5fb 100644
--- a/dev_tools/requirements/envs/pytest-extra.env.txt
+++ b/dev_tools/requirements/envs/pytest-extra.env.txt
@@ -1170,6 +1170,31 @@ protobuf==7.35.0 \
     # via
     #   -c dev_tools/requirements/envs/dev.env.txt
     #   tensorflow-docs
+psutil==7.2.2 \
+    --hash=sha256:0746f5f8d406af344fd547f1c8daa5f5c33dbc293bb8d6a16d80b4bb88f59372 \
+    --hash=sha256:076a2d2f923fd4821644f5ba89f059523da90dc9014e85f8e45a5774ca5bc6f9 \
+    --hash=sha256:11fe5a4f613759764e79c65cf11ebdf26e33d6dd34336f8a337aa2996d71c841 \
+    --hash=sha256:1a571f2330c966c62aeda00dd24620425d4b0cc86881c89861fbc04549e5dc63 \
+    --hash=sha256:1a7b04c10f32cc88ab39cbf606e117fd74721c831c98a27dc04578deb0c16979 \
+    --hash=sha256:1fa4ecf83bcdf6e6c8f4449aff98eefb5d0604bf88cb883d7da3d8d2d909546a \
+    --hash=sha256:2edccc433cbfa046b980b0df0171cd25bcaeb3a68fe9022db0979e7aa74a826b \
+    --hash=sha256:7b6d09433a10592ce39b13d7be5a54fbac1d1228ed29abc880fb23df7cb694c9 \
+    --hash=sha256:8c233660f575a5a89e6d4cb65d9f938126312bca76d8fe087b947b3a1aaac9ee \
+    --hash=sha256:917e891983ca3c1887b4ef36447b1e0873e70c933afc831c6b6da078ba474312 \
+    --hash=sha256:ab486563df44c17f5173621c7b198955bd6b613fb87c71c161f827d3fb149a9b \
+    --hash=sha256:ae0aefdd8796a7737eccea863f80f81e468a1e4cf14d926bd9b6f5f2d5f90ca9 \
+    --hash=sha256:b0726cecd84f9474419d67252add4ac0cd9811b04d61123054b9fb6f57df6e9e \
+    --hash=sha256:b58fabe35e80b264a4e3bb23e6b96f9e45a3df7fb7eed419ac0e5947c61e47cc \
+    --hash=sha256:c7663d4e37f13e884d13994247449e9f8f574bc4655d509c3b95e9ec9e2b9dc1 \
+    --hash=sha256:e452c464a02e7dc7822a05d25db4cde564444a67e58539a00f929c51eddda0cf \
+    --hash=sha256:e78c8603dcd9a04c7364f1a3e670cea95d51ee865e4efb3556a3a63adef958ea \
+    --hash=sha256:eb7e81434c8d223ec4a219b5fc1c47d0417b12be7ea866e24fb5ad6e84b3d988 \
+    --hash=sha256:ed0cace939114f62738d808fdcecd4c869222507e266e574799e9c0faa17d486 \
+    --hash=sha256:eed63d3b4d62449571547b60578c5b2c4bcccc5387148db46e0c2313dad0ee00 \
+    --hash=sha256:fd04ef36b4a6d599bbdb225dd1d3f51e00105f6d48a28f006da7f9822f2606d8
+    # via
+    #   -c dev_tools/requirements/envs/dev.env.txt
+    #   -r dev_tools/requirements/deps/pytest.txt
 pubchempy==1.0.5 \
     --hash=sha256:08f0b2a82a5caa5d61e14935d655da554602d7b5686fe661ab584c882ffff623 \
     --hash=sha256:e936cfed31fa194042ad463be3c803dde5b12ef2f795caf336e3114127c34fa0
diff --git a/dev_tools/requirements/envs/pytest.env.txt b/dev_tools/requirements/envs/pytest.env.txt
index b116bc55b..bc704731f 100644
--- a/dev_tools/requirements/envs/pytest.env.txt
+++ b/dev_tools/requirements/envs/pytest.env.txt
@@ -1076,6 +1076,31 @@ protobuf==7.35.0 \
     # via
     #   -c dev_tools/requirements/envs/dev.env.txt
     #   tensorflow-docs
+psutil==7.2.2 \
+    --hash=sha256:0746f5f8d406af344fd547f1c8daa5f5c33dbc293bb8d6a16d80b4bb88f59372 \
+    --hash=sha256:076a2d2f923fd4821644f5ba89f059523da90dc9014e85f8e45a5774ca5bc6f9 \
+    --hash=sha256:11fe5a4f613759764e79c65cf11ebdf26e33d6dd34336f8a337aa2996d71c841 \
+    --hash=sha256:1a571f2330c966c62aeda00dd24620425d4b0cc86881c89861fbc04549e5dc63 \
+    --hash=sha256:1a7b04c10f32cc88ab39cbf606e117fd74721c831c98a27dc04578deb0c16979 \
+    --hash=sha256:1fa4ecf83bcdf6e6c8f4449aff98eefb5d0604bf88cb883d7da3d8d2d909546a \
+    --hash=sha256:2edccc433cbfa046b980b0df0171cd25bcaeb3a68fe9022db0979e7aa74a826b \
+    --hash=sha256:7b6d09433a10592ce39b13d7be5a54fbac1d1228ed29abc880fb23df7cb694c9 \
+    --hash=sha256:8c233660f575a5a89e6d4cb65d9f938126312bca76d8fe087b947b3a1aaac9ee \
+    --hash=sha256:917e891983ca3c1887b4ef36447b1e0873e70c933afc831c6b6da078ba474312 \
+    --hash=sha256:ab486563df44c17f5173621c7b198955bd6b613fb87c71c161f827d3fb149a9b \
+    --hash=sha256:ae0aefdd8796a7737eccea863f80f81e468a1e4cf14d926bd9b6f5f2d5f90ca9 \
+    --hash=sha256:b0726cecd84f9474419d67252add4ac0cd9811b04d61123054b9fb6f57df6e9e \
+    --hash=sha256:b58fabe35e80b264a4e3bb23e6b96f9e45a3df7fb7eed419ac0e5947c61e47cc \
+    --hash=sha256:c7663d4e37f13e884d13994247449e9f8f574bc4655d509c3b95e9ec9e2b9dc1 \
+    --hash=sha256:e452c464a02e7dc7822a05d25db4cde564444a67e58539a00f929c51eddda0cf \
+    --hash=sha256:e78c8603dcd9a04c7364f1a3e670cea95d51ee865e4efb3556a3a63adef958ea \
+    --hash=sha256:eb7e81434c8d223ec4a219b5fc1c47d0417b12be7ea866e24fb5ad6e84b3d988 \
+    --hash=sha256:ed0cace939114f62738d808fdcecd4c869222507e266e574799e9c0faa17d486 \
+    --hash=sha256:eed63d3b4d62449571547b60578c5b2c4bcccc5387148db46e0c2313dad0ee00 \
+    --hash=sha256:fd04ef36b4a6d599bbdb225dd1d3f51e00105f6d48a28f006da7f9822f2606d8
+    # via
+    #   -c dev_tools/requirements/envs/dev.env.txt
+    #   -r dev_tools/requirements/deps/pytest.txt
 pubchempy==1.0.5 \
     --hash=sha256:08f0b2a82a5caa5d61e14935d655da554602d7b5686fe661ab584c882ffff623 \
     --hash=sha256:e936cfed31fa194042ad463be3c803dde5b12ef2f795caf336e3114127c34fa0
diff --git a/dev_tools/requirements/max_compat/pytest-max-compat.env.txt b/dev_tools/requirements/max_compat/pytest-max-compat.env.txt
index 082214d2c..149899e82 100644
--- a/dev_tools/requirements/max_compat/pytest-max-compat.env.txt
+++ b/dev_tools/requirements/max_compat/pytest-max-compat.env.txt
@@ -992,6 +992,29 @@ protobuf==7.35.0 \
     --hash=sha256:f05bcadf9a2a6b8dda047007075135fb7d08c73d9177aabc067e1be46881a201 \
     --hash=sha256:fcbe42a4ac09d3ec9c987ddfcd956afd0b15f1ff613bd8371bde9405ffd5c8e5
     # via tensorflow-docs
+psutil==7.2.2 \
+    --hash=sha256:0746f5f8d406af344fd547f1c8daa5f5c33dbc293bb8d6a16d80b4bb88f59372 \
+    --hash=sha256:076a2d2f923fd4821644f5ba89f059523da90dc9014e85f8e45a5774ca5bc6f9 \
+    --hash=sha256:11fe5a4f613759764e79c65cf11ebdf26e33d6dd34336f8a337aa2996d71c841 \
+    --hash=sha256:1a571f2330c966c62aeda00dd24620425d4b0cc86881c89861fbc04549e5dc63 \
+    --hash=sha256:1a7b04c10f32cc88ab39cbf606e117fd74721c831c98a27dc04578deb0c16979 \
+    --hash=sha256:1fa4ecf83bcdf6e6c8f4449aff98eefb5d0604bf88cb883d7da3d8d2d909546a \
+    --hash=sha256:2edccc433cbfa046b980b0df0171cd25bcaeb3a68fe9022db0979e7aa74a826b \
+    --hash=sha256:7b6d09433a10592ce39b13d7be5a54fbac1d1228ed29abc880fb23df7cb694c9 \
+    --hash=sha256:8c233660f575a5a89e6d4cb65d9f938126312bca76d8fe087b947b3a1aaac9ee \
+    --hash=sha256:917e891983ca3c1887b4ef36447b1e0873e70c933afc831c6b6da078ba474312 \
+    --hash=sha256:ab486563df44c17f5173621c7b198955bd6b613fb87c71c161f827d3fb149a9b \
+    --hash=sha256:ae0aefdd8796a7737eccea863f80f81e468a1e4cf14d926bd9b6f5f2d5f90ca9 \
+    --hash=sha256:b0726cecd84f9474419d67252add4ac0cd9811b04d61123054b9fb6f57df6e9e \
+    --hash=sha256:b58fabe35e80b264a4e3bb23e6b96f9e45a3df7fb7eed419ac0e5947c61e47cc \
+    --hash=sha256:c7663d4e37f13e884d13994247449e9f8f574bc4655d509c3b95e9ec9e2b9dc1 \
+    --hash=sha256:e452c464a02e7dc7822a05d25db4cde564444a67e58539a00f929c51eddda0cf \
+    --hash=sha256:e78c8603dcd9a04c7364f1a3e670cea95d51ee865e4efb3556a3a63adef958ea \
+    --hash=sha256:eb7e81434c8d223ec4a219b5fc1c47d0417b12be7ea866e24fb5ad6e84b3d988 \
+    --hash=sha256:ed0cace939114f62738d808fdcecd4c869222507e266e574799e9c0faa17d486 \
+    --hash=sha256:eed63d3b4d62449571547b60578c5b2c4bcccc5387148db46e0c2313dad0ee00 \
+    --hash=sha256:fd04ef36b4a6d599bbdb225dd1d3f51e00105f6d48a28f006da7f9822f2606d8
+    # via -r dev_tools/requirements/deps/pytest.txt
 pubchempy==1.0.5 \
     --hash=sha256:08f0b2a82a5caa5d61e14935d655da554602d7b5686fe661ab584c882ffff623 \
     --hash=sha256:e936cfed31fa194042ad463be3c803dde5b12ef2f795caf336e3114127c34fa0