From e24f81f1ee4dba0bd189ac7df33f209bb31b3e24 Mon Sep 17 00:00:00 2001
From: "Marco A. Lopez-Sanchez" <marcoalopez@protonmail.com>
Date: Thu, 11 Jul 2024 14:08:40 +0200
Subject: [PATCH] minor corrections in modules

---
 src/christoffel.py  | 40 ----------------------------------------
 src/tensor_tools.py | 14 +++++++-------
 2 files changed, 7 insertions(+), 47 deletions(-)

diff --git a/src/christoffel.py b/src/christoffel.py
index 97e0621..1a5e696 100644
--- a/src/christoffel.py
+++ b/src/christoffel.py
@@ -124,46 +124,6 @@ def christoffel_wave_speeds(
         pass
 
 
-def _rearrange_tensor(Cij: np.ndarray) -> np.ndarray:
-    """Rearrange a 6x6 (rank 2, dimension 6) elastic tensor into
-    a 3x3x3x3 (rank 4, dimension 3) elastic tensor according to
-    Voigt notation. This rearranging improves tensor operations
-    while maintaining the original information.
-
-    Parameters
-    ----------
-    Cij : numpy.ndarray
-        The 6x6 elastic tensor in Voigt notation.
-
-    Returns
-    -------
-    numpy.ndarray of shape (3, 3, 3, 3).
-        The equivalent 3x3x3x3 elastic tensor
-
-    Notes
-    -----
-    The function uses a dictionary, `voigt_notation`, to map the
-    indices from the 6x6 tensor to the 3x3x3x3 tensor in Voigt
-    notation. The resulting tensor, Cijkl, is calculated by
-    rearranging elements from the input tensor, Cij, according to
-    the mapping.
-    """
-
-    voigt_notation = {0: 0, 11: 1, 22: 2, 12: 3, 21: 3, 2: 4, 20: 4, 1: 5, 10: 5}
-
-    Cijkl = np.zeros((3, 3, 3, 3))
-
-    for L in range(3):
-        for k in range(3):
-            for j in range(3):
-                for i in range(3):
-                    Cijkl[i, j, k, L] = Cij[
-                        voigt_notation[10 * i + j], voigt_notation[10 * k + L]
-                    ]
-
-    return Cijkl
-
-
 def _christoffel_matrix(wavevectors: np.ndarray, Cijkl: np.ndarray) -> np.ndarray:
     """Calculate the Christoffel matrix for a given wave vector
     and elastic tensor Cij.
diff --git a/src/tensor_tools.py b/src/tensor_tools.py
index a3b93f9..06701a8 100644
--- a/src/tensor_tools.py
+++ b/src/tensor_tools.py
@@ -64,10 +64,10 @@ def _symmetrise_tensor(tensor: np.ndarray) -> np.ndarray:
 
 
 def _rearrange_tensor(Cij: np.ndarray) -> np.ndarray:
-    """Rearrange a 6x6 (rank 2, dimension 6) elastic tensor into
-    a 3x3x3x3 (rank 4, dimension 3) elastic tensor according to
-    Voigt notation. This rearranging improves tensor operations
-    while maintaining the original information.
+    """Rearranges the 6x6 (rank 2, dimension 6) stiffness (elastic)
+    matrix in Voigt notation into a 3x3x3x3 (rank 4, dimension 3)
+    stiffness tensor. This rearrangement is necessary to perform
+    tensor operations while retaining the original information.
 
     Parameters
     ----------
@@ -270,7 +270,7 @@ def rotate_stiffness_tensor(
     rotation_axis: str = "z"
     ) -> tuple[np.ndarray, np.ndarray]:
     """Rotates a stiffness matrix (Voigt notation) or a
-    stiffness tensor around a specified axis. The rotation
+    stiffness tensor aabout a specified axis. The rotation
     is performed in the right-handed coordinate system taking
     into account the following reference frame:
 
@@ -306,13 +306,13 @@ def rotate_stiffness_tensor(
     if not isinstance(rotation_axis, str):
         raise ValueError("rotation_axis should be a string.")
 
-    if stiffness_tensor.shape != (3, 3, 3, 3) or stiffness_tensor.shape != (6, 6):
+    if not (stiffness_tensor.shape == (3, 3, 3, 3) or stiffness_tensor.shape == (6, 6)):
         raise ValueError(
             "Input stiffness array must be 3x3x3x3 or 6x6 (Voigt notation)"
         )
 
     # convert 6x6 to 3x3x3x3
-    if stiffness_tensor.shape != (6, 6):
+    if stiffness_tensor.shape == (6, 6):
         stiffness_tensor = _rearrange_tensor(stiffness_tensor)
 
     # generate the rotation