Merge pull request #133 from ShikharJ/Issue132

Implemented DenseMatrix.reshape() function

Author: isuruf

symengine/lib/symengine.pxd

@@ -619,6 +619,7 @@ cdef extern from "<symengine/matrix.h>" namespace "SymEngine":
         DenseMatrix()
         DenseMatrix(unsigned i, unsigned j) nogil
         DenseMatrix(unsigned i, unsigned j, const vec_basic &v) nogil
+        void resize(unsigned i, unsigned j) nogil
 
     bool is_a_DenseMatrix "SymEngine::is_a<SymEngine::DenseMatrix>"(const MatrixBase &b) nogil
     DenseMatrix* static_cast_DenseMatrix "static_cast<SymEngine::DenseMatrix*>"(const MatrixBase *a)

symengine/lib/symengine_wrapper.pyx

@@ -1740,6 +1740,13 @@ cdef class DenseMatrix(MatrixBase):
         def __get__(self):
             return self.nrows()*self.ncols()
 
+    def reshape(self, rows, cols):
+        if len(self) != rows*cols:
+            raise ValueError("Invalid reshape parameters %d %d" % (rows, cols))
+        r = DenseMatrix(self)
+        deref(symengine.static_cast_DenseMatrix(r.thisptr)).resize(rows, cols)
+        return r
+
     def _get_index(self, i, j):
         nr = self.nrows()
         nc = self.ncols()

symengine/tests/test_matrices.py

@@ -289,6 +289,13 @@ def test_shape():
     A = DenseMatrix(2, 2, [1, 2, 3, 4])
     assert A.shape == (2, 2)
 
+def test_reshape():
+    A = DenseMatrix(2, 2, [1, 2, 3, 4])
+    B = DenseMatrix(4, 1, [1, 2, 3, 4])
+    C = A.reshape(4, 1)
+    assert C == B
+    assert C != A
+
 #@pytest.mark.skipif(not HAVE_NUMPY, reason='requires numpy')
 def test_dump_real():
     if not HAVE_NUMPY:  # nosetests work-around