fixes #147

Author: ShikharJ

symengine/lib/symengine_wrapper.pyx

@@ -2171,9 +2171,6 @@ cdef class ImmutableDenseMatrix(DenseMatrixBase):
     def set(self, i, j, e):
         raise TypeError("Cannot set values of {}".format(self.__class__))
 
-    def _set(self, i, j, e):
-        raise TypeError("Cannot set values of {}".format(self.__class__))
-
 ImmutableMatrix = ImmutableDenseMatrix
 
 cdef matrix_to_vec(DenseMatrixBase d, symengine.vec_basic& v):

symengine/tests/test_matrices.py

@@ -395,3 +395,8 @@ def test_immutablematrix():
     X = ImmutableMatrix([[1, 2], [3, 4]])
     Y = ImmutableMatrix([[1], [0]])
     assert type(X.LUsolve(Y)) == ImmutableMatrix
+
+    x = Symbol("x")
+    X = ImmutableMatrix([[1, 2], [3, 4]])
+    Y = ImmutableMatrix([[1, 2], [x, 4]])
+    assert Y.subs(x, 3) == X