BUG: sparse: fixed the resize() method of dok_matrix (ticket #997); t…

…hanks to jap for report and patch.

scipy/sparse/dok.py

@@ -531,8 +531,9 @@ def toarray(self):
         return self.tocoo().toarray()
 
     def resize(self, shape):
-        """ Resize the matrix to dimensions given by 'shape', removing any
-        non-zero elements that lie outside.
+        """ Resize the matrix in-place to dimensions given by 'shape'.
+        
+        Any non-zero elements that lie outside the new shape are removed.
         """
         if not isshape(shape):
             raise TypeError("dimensions must be a 2-tuple of positive"
@@ -544,7 +545,7 @@ def resize(self, shape):
             for (i, j) in self.keys():
                 if i >= newM or j >= newN:
                     del self[i, j]
-        self.shape = shape
+        self._shape = shape
 
 
 

scipy/sparse/tests/test_base.py

@@ -1298,6 +1298,21 @@ def test_ctor(self):
         c = csr_matrix(b)
         assert_equal(A.todense(), c.todense())
 
+    def test_resize(self):
+        """A couple basic tests of the resize() method.
+        
+        resize(shape) resizes the array in-place.
+        """
+        a = dok_matrix((5,5))
+        a[:,0] = 1
+        a.resize((2,2))
+        expected1 = array([[1,0],[1,0]])
+        assert_array_equal(a.todense(), expected1)
+        a.resize((3,2))
+        expected2 = array([[1,0],[1,0],[0,0]])
+        assert_array_equal(a.todense(), expected2)
+
+
     def test_ticket1160(self):
         """Regression test for ticket #1160."""
         a = dok_matrix((3,3))