Merge pull request #184 from isuruf/div

div for matrices

Author: isuruf

symengine/lib/symengine_wrapper.pyx

@@ -3087,6 +3087,12 @@ cdef class DenseMatrixBase(MatrixBase):
         else:
             return NotImplemented
 
+    def __div__(a, b):
+        return div_matrices(a, b)
+
+    def __truediv__(a, b):
+        return div_matrices(a, b)
+
     def __sub__(a, b):
         a = _sympify(a, False)
         b = _sympify(b, False)
@@ -3556,6 +3562,20 @@ cdef class DenseMatrixBase(MatrixBase):
     def expand(self, *args, **kwargs):
         return self.applyfunc(lambda x : x.expand())
 
+
+def div_matrices(a, b):
+    a = _sympify(a, False)
+    b = _sympify(b, False)
+    if isinstance(a, MatrixBase):
+        if isinstance(b, MatrixBase):
+            return a.mul_matrix(b.inv())
+        elif isinstance(b, Basic):
+            return a.mul_scalar(1/b)
+        else:
+            return NotImplemented
+    else:
+        return NotImplemented
+
 class DenseMatrixBaseIter(object):
 
     def __init__(self, d):

symengine/tests/test_matrices.py

@@ -217,6 +217,19 @@ def test_sub():
     raises(TypeError, lambda: 5 - A)
 
 
+def test_div():
+    w, x, y, z = symbols("w, x, y, z")
+    A = DenseMatrix([[w, x], [y, z]])
+    B = DenseMatrix([[1, 1], [1, 0]])
+    C = DenseMatrix([[x, w - x], [z, y - z]])
+
+    assert A / 2 == DenseMatrix([[w/2, x/2], [y/2, z/2]])
+    assert C * B == A
+    assert A / B == C
+
+    raises(TypeError, lambda: 2/A)
+
+
 def test_transpose():
     A = DenseMatrix(3, 3, [1, 2, 3, 4, 5, 6, 7, 8, 9])