Merge 49bc761 into 43ca7b7

tests/test_matrix.py

@@ -310,3 +310,15 @@ def test_determinant():
         for i in mat.determinant():
             a += i.__str__()
         assert a == "{1.0}"
+
+
+def test_cofactor():
+    mat = getTokens('[1,2;3,4]')
+    if mat.isSquare():
+        assert str(mat.cofactor()) == '[{4.0},{-3.0};{-2.0},{1.0}]'
+    mat = getTokens('[1,2,3;0,4,5;1,0,6]')
+    if mat.isSquare():
+        assert str(mat.cofactor()) == '[{24.0},{5.0},{-4.0};{-12.0},{3.0},{2.0};{-2.0},{-5.0},{4.0}]'
+    mat = getTokens('[1,2,3,4;5,6,7,8;9,10,11,12;13,14,15,16]')
+    if mat.isSquare():
+        assert str(mat.cofactor()) == '[{0},{0},{0},{0};{0},{0},{0},{0};{0},{0},{0},{0};{0},{0},{0},{0}]'

visma/matrix/structure.py

@@ -105,9 +105,6 @@ def isDiagonal(self):
     def inverse(self):
         pass
 
-    def cofactor(self):
-        pass
-
     def dimension(self):
         """Gets the dimension of the matrix
 
@@ -196,6 +193,31 @@ def traceMat(self):
         trace, _, _, _, _ = simplify(trace)
         return trace
 
+    def cofactor(self):
+        """Calculates cofactors matrix of the Square Matrix
+
+        Returns:
+            An object of type SquareMat
+        """
+        mat1 = SquareMat()
+        mat1.value = []
+        for i in range(self.dim[0]):
+            if(i % 2 == 0):
+                coeff = -1
+            else:
+                coeff = 1
+            mat1.value.append([])
+            for j in range(self.dim[1]):
+                coeff *= -1
+                mat = SquareMat()
+                temp = np.array(self.value)
+                mat.value = np.concatenate((np.concatenate((temp[:i, :j], temp[i+1:, :j])), np.concatenate((temp[:i, j+1:], temp[i+1:, j+1:]))), axis=1).tolist()
+                val = mat.determinant()[0]
+                val.value *= coeff
+                mat1.value[i].append([val])
+        mat1.dimension()
+        return mat1
+
 
 class DiagMat(SquareMat):
     """Class for Diagonal matrix