Merge pull request #3511 from yingzha/ccw

theano/tensor/opt.py

@@ -3703,6 +3703,22 @@ register_canonicalize(local_reshape_chain(T.Reshape),
                       name='local_reshape_chain')
 
 
+@register_canonicalize
+@register_stabilize
+@gof.local_optimizer([T.Reshape])
+def local_useless_reshape(node):
+    """
+    Remove Reshape when both the input and the output have a
+    single dimension.
+
+    """
+    if isinstance(node.op, T.Reshape):
+        if (node.inputs[0].ndim == 1 and node.outputs[0].ndim == 1 and
+                node.inputs[0].broadcastable ==
+                node.outputs[0].broadcastable):
+            return [node.inputs[0]]
+
+
 @register_canonicalize
 @register_stabilize
 @gof.local_optimizer([T.Reshape])

theano/tensor/tests/test_opt.py

@@ -3135,7 +3135,7 @@ def test_local_fill_useless():
     assert T.Alloc in ops
     f(m_, x_)
 
-    
+
 class Test_local_useless_elemwise_comparison(unittest.TestCase):
     def test_local_useless_elemwise_comparison(self):
         # TODO: test each case individually.
@@ -3171,7 +3171,7 @@ class Test_local_useless_elemwise_comparison(unittest.TestCase):
          >Sum{acc_dtype=float64} [id L] ''
          > |X[t] [id M] -> [id I]
         """
-        
+
         mode = theano.compile.get_default_mode().excluding('fusion')
         f = theano.function([X, Y], Z, mode=mode)
         theano.printing.debugprint(f, print_type=True)
@@ -3211,7 +3211,7 @@ class Test_local_useless_elemwise_comparison(unittest.TestCase):
         assert len(elem.inputs) == 1, elem.inputs
         assert isinstance(elem.inputs[0], T.TensorConstant), elem
         assert T.extract_constant(elem.inputs[0]) == val, val
-    
+
     def assert_identity(self, f):
         topo = f.maker.fgraph.toposort()
         assert len(topo) == 1
@@ -3224,10 +3224,10 @@ class Test_local_useless_elemwise_comparison(unittest.TestCase):
     def test_inequality_with_self(self):
         x = T.scalar('x', dtype=config.floatX)
         mode = theano.compile.get_default_mode().including('local_useless_elemwise_comparison')
-        
+
         f = theano.function([x], T.lt(x, x), mode=mode)
         self.assert_eqs_const(f, 0)
-        
+
         f = theano.function([x], T.le(x, x), mode=mode)
         self.assert_eqs_const(f, 1)
 
@@ -3289,10 +3289,10 @@ class Test_local_useless_elemwise_comparison(unittest.TestCase):
 
         f = theano.function([x, y], T.ge(x.shape[0]+y.shape[0], 0), mode=mode)
         self.assert_eqs_const(f, 1)
-        
+
     def test_and(self):
         mode = theano.compile.get_default_mode().including('canonicalize')
-        
+
         x = T.scalar('x', dtype='int8')
 
         f = theano.function([x], T.and_(x, 0), mode=mode)
@@ -5704,7 +5704,7 @@ def test_local_flatten_lift():
 
 class Test_Reshape(unittest.TestCase):
     def setUp(self):
-        self.mode = mode_opt 
+        self.mode = mode_opt
         self.op = tensor.Reshape
 
     def test_local_reshape(self):
@@ -5716,6 +5716,16 @@ class Test_Reshape(unittest.TestCase):
         assert sum(isinstance(node.op, self.op) for node in topo) == 1
 
 
+def test_local_useless_reshape():
+    mode = theano.compile.get_default_mode().including(
+            'local_useless_reshape')
+    i = T.iscalar('i')
+    m = theano.tensor.mgrid[0:i,]
+    f = theano.function([i], m, mode=mode)
+    topo = f.maker.fgraph.toposort()
+    assert not any(isinstance(n.op, tensor.basic.Reshape) for n in topo)
+
+
 def test_local_reshape_lift():
     x = tensor.tensor4()
     out = T.exp(x).reshape([x.size])