fix a bug in theano.get_constant_value and add test for it.

theano/tensor/basic.py

@@ -372,7 +372,7 @@ def get_constant_value(v):
             return ret[0][0]
         if isinstance(v.owner.op, Subtensor) and v.ndim==0:
             if isinstance(v.owner.inputs[0], TensorConstant):
-                return v.owner.inputs[0].data[v.owner.op.idx_list[0]]
+                return v.owner.inputs[0].data.__getitem__(tuple(v.owner.op.idx_list))
 
             # The index list 'idx_list' should have length one
             # since joining scalar variables results in a 1D vector.

theano/tensor/tests/test_basic.py

@@ -3575,6 +3575,15 @@ class T_get_constant_value(unittest.TestCase):
         v = tensor.row()
         assert get_constant_value(v.shape[0])==1
 
+    def test_subtensor_of_constant(self):
+        c = constant(numpy.random.rand(5))
+        for i in range(c.value.shape[0]):
+            assert get_constant_value(c[i]) == c.value[i]
+        c = constant(numpy.random.rand(5,5))
+        for i in range(c.value.shape[0]):
+            for j in range(c.value.shape[1]):
+                assert get_constant_value(c[i,j]) == c.value[i,j]
+
 if __name__ == '__main__':
     if 1:
         unittest.main()