Reformat constructor of class Matrix in matrix.py to match to non-None values instead of instance checking;

More implementation of operators in class Matrix

src/matrix.py

@@ -33,18 +33,11 @@ class Matrix:
 
         :rtype: Matrix
         """
-        if isinstance(data, numpy.ndarray):
+        # Case Matrix(str, int)
-            try:
+        if n is not None and model is not None:
-                data.shape[1]
+            ...  # TODO: what shall one do here?
-            except IndexError:
+        # Case: Matrix(list, str, int)
-                self.__shape__ = (data.shape[0], 1)
+        elif n is not None and structure is not None and data is not None:
-            else:
-                self.__shape__ = data.shape
-            self.__data__ = data
-        elif isinstance(data, list) and isinstance(shape, tuple):
-            self.__shape__ = shape
-            self.__data__ = numpy.array(data).reshape(shape)
-        elif isinstance(data, list) and isinstance(structure, str) and isinstance(n, int):
             if structure == "unity":
                 ...  # TODO: what does it mean?
             elif structure == "diagonal":
@@ -57,8 +50,19 @@ class Matrix:
                 tridiag = numpy.diag([data[0]] * (n-1), -1) + numpy.diag([data[1]] * n, 0) + numpy.diag([data[2]] * (n-1), 1)
                 self.__data__ = tridiag
                 self.__shape__ = tridiag.shape
-        elif isinstance(model, str) and isinstance(n, int):
+        # Case: Matrix(list, str, int)
-            ...  # TODO: what shall one do here?
+        elif shape is not None and data is not None:
+            self.__shape__ = shape
+            self.__data__ = numpy.array(data).reshape(shape)
+        # Case: Matrix(numpy.ndarray)
+        elif data is not None:
+            try:
+                data.shape[1]
+            except IndexError:
+                self.__shape__ = (data.shape[0], 1)
+            else:
+                self.__shape__ = data.shape
+            self.__data__ = data
         else:
             raise ValueError("Only following signatures are allowed: (numpy.ndarray), (list, tuple), (list, str, int), (str, int)")
 
@@ -85,16 +89,53 @@ class Matrix:
         Return ``self==value``
 
         :param other: The object to compare to; must be either a ``Matrix``, a ``list`` or a ``numpy.ndarray``
-        :return: True if data in the matrix is totally equal to the given data in other, otherwise False
+        :return: True if data in the matrix are equal to the given data in other for each component, otherwise False
         """
         if isinstance(other, Matrix):
-            return (self.__data__ == other.__data__).all()
+            to_compare = other.__data__
         elif isinstance(other, list):
-            return (self.__data__ == numpy.array(other)).all()
+            to_compare = numpy.array(other)
         elif isinstance(other, numpy.ndarray):
-            return (self.__data__ == other).all()
+            to_compare = other
         else:
             raise ValueError("Matrix type is not comparable to type of given ``other``")
+        return (self.__data__ == to_compare).all()
 
     def __str__(self):
         return str(self.__data__)
+
+    def __neg__(self):
+        return Matrix(-self.__data__)
+
+    def __add__(self, other):
+        if isinstance(other, Matrix):
+            if self.__shape__ != other.__shape__:
+                raise ValueError("The shape of the operands must be the same")
+            return self.__data__ + other.__data__
+        elif isinstance(other, int) or isinstance(other, float):
+            return self.__data__ + other
+        else:
+            raise ValueError("Only a number or another ``Matrix`` can be added to a ``Matrix``")
+
+    def __radd__(self, other):
+        return self + other
+
+    def __sub__(self, other):
+        return self + (-other)
+
+    def __rsub__(self, other):
+        return -self + other
+
+    def __truediv__(self, other):
+        if isinstance(other, int) or isinstance(other, float):
+            return self.__data__ / other
+        else:
+            raise ValueError("A ``Matrix`` can only be divided ba a number")
+
+    def __mul__(self, other):
+        if isinstance(other, Matrix):
+            if self.__shape__[1] != other.__shape__[0]:
+                raise ValueError("The amount of columns of the first operand must match the amount of rows of the second operand")
+            return Matrix(self.__data__ * other.__data__)
+        elif isinstance(other, int) or isinstance(other, float):
+            ...

test/test_matrix.py

@@ -86,6 +86,18 @@ class TestMatrix(TestCase):
         expected = [[1, -1, 0, 0], [-1, 1, -1, 0], [0, -1, 1, -1], [0, 0, -1, 1]]
         self.assertEqual(expected, actual)
 
+    def test_matrices_should_be_equal(self):
+        m1 = Matrix([1, 2, 3, 4], (2, 2))
+        m2 = Matrix([1, 2, 3, 4], (2, 2))
+
+        self.assertEqual(m1, m2)
+
+    def test_matrices_should_not_be_equal(self):
+        m1 = Matrix([1, 2, 3, 4], (2, 2))
+        m2 = Matrix([1, 2, 3, 3], (2, 2))
+
+        self.assertNotEqual(m1, m2)
+
     def test_should_transpose_matrix(self):
         data = [1, 2, 3, 4, 5, 6, 7, 8, 9]
         actual = Matrix(data, (3, 3))
@@ -93,3 +105,116 @@ class TestMatrix(TestCase):
         actual = actual.transpose()
         expected = [[1, 4, 7], [2, 5, 8], [3, 6, 9]]
         self.assertEqual(expected, actual)
+
+    def test_should_negate_matrix(self):
+        m = Matrix([1, 2, 3, 4], (2, 2))
+
+        actual = -m
+        expected = Matrix([-1, -2, -3, -4], (2, 2))
+
+        self.assertEqual(expected, actual)
+
+    def test_should_add_two_matrices(self):
+        m1 = Matrix([1, 2, 3, 4], (2, 2))
+        m2 = Matrix([4, 3, 2, 1], (2, 2))
+
+        actual = m1 + m2
+        expected = Matrix([5, 5, 5, 5], (2, 2))
+
+        self.assertEqual(expected, actual)
+
+    def test_should_add_scalar_to_matrix(self):
+        m = Matrix([1, 2, 3, 4], (2, 2))
+        s = 5
+
+        actual = m + s
+        expected = Matrix([6, 7, 8, 9], (2, 2))
+
+        self.assertEqual(expected, actual)
+
+    def test_should_radd_scalar_to_matrix(self):
+        m = Matrix([1, 2, 3, 4], (2, 2))
+        s = 5
+
+        actual = s + m
+        expected = Matrix([6, 7, 8, 9], (2, 2))
+
+        self.assertEqual(expected, actual)
+
+    def test_should_raise_shape_missmatch_error_while_adding_vectors(self):
+        m1 = Matrix([1, 2, 3, 4], (2, 2))
+        m2 = Matrix([1, 2], (2, 1))
+
+        self.assertRaises(ValueError, lambda: m1 + m2)
+
+    def test_should_raise_value_missmatch_error_while_adding_vectors(self):
+        m = Matrix([1, 2, 3, 4], (2, 2))
+        o = ""
+
+        self.assertRaises(ValueError, lambda: m + o)
+
+    def test_should_sub_two_matrices(self):
+        m1 = Matrix([1, 2, 3, 4], (2, 2))
+        m2 = Matrix([4, 3, 2, 1], (2, 2))
+
+        actual = m1 - m2
+        expected = Matrix([-3, -1, 1, 3], (2, 2))
+
+        self.assertEqual(expected, actual)
+
+    def test_should_sub_scalar_of_matrix(self):
+        m = Matrix([1, 2, 3, 4], (2, 2))
+        s = 5
+
+        actual = m - s
+        expected = Matrix([-4, -3, -2, -1], (2, 2))
+
+        self.assertEqual(expected, actual)
+
+    def test_should_rsub_scalar_of_matrix(self):
+        m = Matrix([1, 2, 3, 4], (2, 2))
+        s = 5
+
+        actual = s - m
+        expected = Matrix([4, 3, 2, 1], (2, 2))
+
+        self.assertEqual(expected, actual)
+
+    def test_should_div_matrix_by_scalar(self):
+        m = Matrix([5, 10, 15, 20], (2, 2))
+        s = 5
+
+        actual = m / s
+        expected = Matrix([1, 2, 3, 4], (2, 2))
+
+        self.assertEqual(expected, actual)
+
+    def test_should_raise_value_missmatch_error_while_dividing_with_other_than_scalar(self):
+        m = Matrix([1, 2, 3, 4], (2, 2))
+        o = ""
+
+        self.assertRaises(ValueError, lambda: m / o)
+
+    def test_should_mul_matrices_1(self):
+        m1 = Matrix([1, 2], (2, 1))
+        m2 = Matrix([3, 4], (1, 2))
+
+        actual = m1 * m2
+        expected = Matrix([3, 4, 6, 8], (2, 2))
+
+        self.assertEqual(expected, actual)
+
+    def test_should_mul_matrices_2(self):
+        m1 = Matrix([1, 2], (1, 2))
+        m2 = Matrix([3, 4], (2, 1))
+
+        actual = m1 * m2
+        expected = Matrix([11], (1, 1))
+
+        self.assertEqual(expected, actual)
+
+    def test_should_raise_shape_missmatch_error_while_multiplying_matrices(self):
+        m1 = Matrix([1, 2], (2, 1))
+        m2 = Matrix([3, 4], (2, 1))
+
+        self.assertRaises(ValueError, lambda: m1 * m2)