An attempt to prepare mask for case S -> A B_i.

Author: gsvgit

cfpq_matrix/block/block_matrix.py

@@ -43,7 +43,14 @@ def mxm(self, other: Matrix, op: Semiring, mask: Matrix, swap_operands: bool = F
                 BlockMatrixOrientation.VERTICAL
                 if swap_operands
                 else BlockMatrixOrientation.HORIZONTAL
-            )        
+            )
+        elif not mask is None:
+            mask = self.block_matrix_space.hyper_rotate(
+                mask,
+                BlockMatrixOrientation.VERTICAL
+                if swap_operands
+                else BlockMatrixOrientation.HORIZONTAL
+                ) 
 
         return self.base.mxm(            
             self.block_matrix_space.hyper_rotate(