update: add reciprocal lattice calcs

src/py/mat3ra/made/lattice.py

@@ -128,6 +128,20 @@ def cell_volume(self) -> float:
     def cell_volume_rounded(self) -> float:
         return self.vectors.volume_rounded
 
+    @property
+    def reciprocal_vectors(self):
+        return np.linalg.inv(np.array(self.vector_arrays, dtype=float)).T.tolist()
+
+    @property
+    def reciprocal_vector_norms(self) -> List[float]:
+        return [float(np.linalg.norm(vector)) for vector in self.reciprocal_vectors]
+
+    @property
+    def reciprocal_vector_ratios(self) -> List[float]:
+        norms = self.reciprocal_vector_norms
+        max_norm = max(norms)
+        return [round(float(value / max_norm), 3) for value in norms]
+
     def get_hash_string(self, is_scaled: bool = False) -> str:
         """Mirrors JS Lattice.getHashString(isScaled). Rounds to HASH_TOLERANCE decimal places."""
         scale = self.a if is_scaled else 1

tests/py/unit/test_lattice.py

@@ -1,3 +1,5 @@
+import pytest
+
 from mat3ra.code.vector import RoundedVector3D
 from mat3ra.made.lattice import Lattice
 from mat3ra.utils import assertion as assertion_utils
@@ -75,5 +77,28 @@ def test_lattice_get_scaled_by_matrix():
     assertion_utils.assert_deep_almost_equal(lattice.vector_arrays, expected_vector_values)
 
 
+def test_reciprocal_vectors():
+    lattice = Lattice(a=2.0, b=3.0, c=4.0)
+    expected_vectors = [[0.5, 0.0, 0.0], [0.0, 1 / 3, 0.0], [0.0, 0.0, 0.25]]
+    assertion_utils.assert_deep_almost_equal(lattice.reciprocal_vectors, expected_vectors)
+
+
+def test_reciprocal_vector_norms():
+    lattice = Lattice(a=2.0, b=3.0, c=4.0)
+    expected_norms = [0.5, 1 / 3, 0.25]
+    assertion_utils.assert_deep_almost_equal(lattice.reciprocal_vector_norms, expected_norms)
+
+
+@pytest.mark.parametrize(
+    "lattice, expected",
+    [
+        (Lattice(a=2.0, b=3.0, c=4.0), [1.0, 0.667, 0.5]),
+        (Lattice(a=5.43, b=5.43, c=5.43), [1.0, 1.0, 1.0]),
+    ],
+)
+def test_reciprocal_vector_ratios(lattice, expected):
+    assert lattice.reciprocal_vector_ratios == expected
+
+
 # to test: create, calculate_vectors, from_vectors, get_lattice_type, clone
 # from_vectors, to_dict, cell, cell_volume, scale_by_matrix, update_from_lattice,