added tests for undefined gradient functionality

theano/tests/test_gradient.py

@@ -3,12 +3,13 @@
 # UNIT TEST
 #
 import unittest
-import numpy
 import theano
 from theano import gof
 
-from theano.gradient import *
+from theano.gradient import grad_sources_inputs
 from theano import gradient
+from theano.tensor.nnet.Conv3D import conv3D
+from theano import config
 
 
 def _grad_sources_inputs(*args):
@@ -265,6 +266,20 @@ def test_unimplemented_grad_func():
     except NotImplementedError:
         pass
 
+def test_undefined_grad_func():
+    #tests that function compilation catches undefined grads in the graph
+    a = theano.tensor.vector()
+    b = theano.gradient.grad_undefined(theano.tensor.add, 0, a)
+    try:
+        f = theano.function([a],b)
+        assert 0
+        #Note: it's important that the GradUndefinedOp is cauhgt at
+        #COMPILATION time, not execution time.
+        #If the uncomputable variable is, for example, multiplied by0,
+        #it could be optimized out of the final graph
+    except theano.gradient.GradUndefinedError:
+        pass
+
 def test_unimplemented_grad_grad():
     #tests that unimplemented grads are caught in the grad method
 
@@ -284,6 +299,24 @@ def test_unimplemented_grad_grad():
     except NotImplementedError:
         pass
 
+def test_undefined_grad_grad():
+    #tests that undefined grads are caught in the grad method
+
+    V = theano.tensor.TensorType(dtype=config.floatX,
+            broadcastable = (False,False,False,False,False))()
+    W = theano.tensor.TensorType(dtype=config.floatX,
+            broadcastable = (False, False, False, False, False))()
+    b = theano.tensor.vector()
+    d = theano.tensor.ivector()
+
+    Z = conv3D(V,W,b,d)
+
+    try:
+        g = theano.gradient.grad(Z.sum(),d)
+        assert False
+    except theano.gradient.GradUndefinedError:
+        pass
+
 def test_grad_name():
     A = theano.tensor.matrix('A')
     x = theano.tensor.vector('x')