Add support for custom message in Assert.

theano/tensor/opt.py

@@ -1363,6 +1363,9 @@ class Assert(T.Op):
     """
     view_map = {0: [0]}
 
+    def __init__(self, msg="Theano Assert failed!"):
+        self.msg = msg
+
     def make_node(self, value, *conds):
         cond = [T.as_tensor_variable(c) for c in conds]
         assert numpy.all([c.type.ndim == 0 for c in cond])
@@ -1375,13 +1378,13 @@ class Assert(T.Op):
         out, = out_
         v = inputs[0]
         out[0] = v
-        assert numpy.all(inputs[1:])
+        assert numpy.all(inputs[1:]), self.msg
 
     def __eq__(self, other):
-        return type(self) == type(other)
+        return type(self) == type(other) and self.msg == other.msg
 
     def __hash__(self):
-        return hash(type(self))
+        return hash(type(self)) ^ hash(self.msg)
 
     def grad(self, input, output_gradients):
         return output_gradients
@@ -1391,12 +1394,13 @@ class Assert(T.Op):
         out = onames[0]
         check = []
         fail = sub['fail']
+        msg = self.msg.replace('"', '\\"').replace('\n', '\\n')
         for idx in xrange(len(inames) - 1):
             i = inames[idx + 1]
             dtype = node.inputs[idx + 1].dtype
             check.append('if(!((npy_%(dtype)s*)PyArray_DATA(%(i)s))[0])'
-                         '{PyErr_SetString(PyExc_AssertionError,"Theano'
-                         ' Assert failed!");%(fail)s}' % locals())
+                         '{PyErr_SetString(PyExc_AssertionError,"%(msg)s");'
+                         '%(fail)s}' % locals())
         check = "\n".join(check)
         return """
         %(check)s
@@ -1405,7 +1409,7 @@ class Assert(T.Op):
         """ % locals()
 
     def c_code_cache_version(self):
-        return (0, 1)
+        return (1, 0)
 
     def infer_shape(self, node, input_shapes):
         return [input_shapes[0]]