[MeshLib] Added a description of getElementRotationMatrices

MeshLib/Utils/GetElementRotationMatrices.h

@@ -17,7 +17,19 @@
 namespace MeshLib
 {
 class Element;
-
+/**
+ * \brief Element rotation matrix computation
+ *
+ *  This function returns a vector containing the rotation matrices of given
+ * elements. The rotation matrix of an element is used to map the
+ * local vector to the global coordinate system. If an element is not inclined,
+ * the identity matrix is used as its rotation matrix.
+ *
+ * @param space_dimension The space dimension.
+ * @param mesh_dimension  The mesh dimension.
+ * @param elements        The mesh elements.
+ * @return A vector of rotation matrices of given elements.
+ */
 std::vector<Eigen::MatrixXd> getElementRotationMatrices(
     int const space_dimension, int const mesh_dimension,
     std::vector<Element*> const& elements);