From 0022a9bc93a62bfb3ad2872a62c477fabc8e5a1c Mon Sep 17 00:00:00 2001
From: eminyouskn <youssouf.emine@artelys.com>
Date: Fri, 19 Jun 2026 11:36:30 -0400
Subject: [PATCH 1/2] KNITROAMPL: prefer \$KNITRODIR/knitroampl/knitroampl for
 executable lookup

Add \$KNITRODIR/knitroampl/knitroampl as the first candidate in
_default_executable(), before the knitro Python package path and the
system PATH fallback. This allows users with a standalone Knitro
installation (no Python package) to be picked up automatically via the
KNITRODIR environment variable.
---
 pyomo/solvers/plugins/solvers/KNITROAMPL.py | 31 ++++++++++++++-------
 1 file changed, 21 insertions(+), 10 deletions(-)

diff --git a/pyomo/solvers/plugins/solvers/KNITROAMPL.py b/pyomo/solvers/plugins/solvers/KNITROAMPL.py
index 930876d7ac6..e4aa659b446 100644
--- a/pyomo/solvers/plugins/solvers/KNITROAMPL.py
+++ b/pyomo/solvers/plugins/solvers/KNITROAMPL.py
@@ -7,6 +7,7 @@
 # software.  This software is distributed under the 3-clause BSD License.
 # ____________________________________________________________________________________
 import logging
+import os
 
 from pyomo.common import Executable
 from pyomo.common.collections import Bunch
@@ -64,17 +65,27 @@ def __init__(self, **kwds):
         self._capabilities.sos2 = False
 
     def _default_executable(self):
-        try:
-            # If knitro Python package is available, use the executable it contains
-            import knitro
-
-            package_knitroampl_path = (
-                pathlib.Path(knitro.__file__).resolve().parent
-                / 'knitroampl'
-                / 'knitroampl'
+        executable = None
+        knitrodir = os.environ.get('KNITRODIR')
+        if knitrodir:
+            knitroampl_path = (
+                pathlib.Path(knitrodir) / 'knitroampl' / 'knitroampl'
             )
-            executable = Executable(str(package_knitroampl_path))
-        except ModuleNotFoundError:
+            executable = Executable(str(knitroampl_path))
+        if not executable:
+            try:
+                # If knitro Python package is available, use the executable it contains
+                import knitro
+
+                package_knitroampl_path = (
+                    pathlib.Path(knitro.__file__).resolve().parent
+                    / 'knitroampl'
+                    / 'knitroampl'
+                )
+                executable = Executable(str(package_knitroampl_path))
+            except ModuleNotFoundError:
+                pass
+        if not executable:
             # Otherwise, search usual path list
             executable = Executable('knitroampl')
         if not executable:

From b739ff96a3af4db9a997a4e0628f934f70f12077 Mon Sep 17 00:00:00 2001
From: eminyouskn <youssouf.emine@artelys.com>
Date: Fri, 19 Jun 2026 11:49:13 -0400
Subject: [PATCH 2/2] black format

---
 pyomo/solvers/plugins/solvers/KNITROAMPL.py | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/pyomo/solvers/plugins/solvers/KNITROAMPL.py b/pyomo/solvers/plugins/solvers/KNITROAMPL.py
index e4aa659b446..0d01418b4c2 100644
--- a/pyomo/solvers/plugins/solvers/KNITROAMPL.py
+++ b/pyomo/solvers/plugins/solvers/KNITROAMPL.py
@@ -68,9 +68,7 @@ def _default_executable(self):
         executable = None
         knitrodir = os.environ.get('KNITRODIR')
         if knitrodir:
-            knitroampl_path = (
-                pathlib.Path(knitrodir) / 'knitroampl' / 'knitroampl'
-            )
+            knitroampl_path = pathlib.Path(knitrodir) / 'knitroampl' / 'knitroampl'
             executable = Executable(str(knitroampl_path))
         if not executable:
             try: