elaborated TensorType.values_eq to implement NaN==NaN

theano/tensor/basic.py

@@ -321,7 +321,16 @@ class TensorType(Type):
             return False
         if a.dtype != b.dtype:
             return False
-        return numpy.all(a==b)
+        a_eq_b = (a==b)
+        r = numpy.all(a_eq_b)
+        if r: return True
+        # maybe the trouble is that there are NaNs 
+        a_missing = numpy.isnan(a)
+        if a_missing.any():
+            b_missing = numpy.isnan(b)
+            return numpy.all(a_eq_b + (a_missing == b_missing))
+        else:
+            return False
     @staticmethod
     def values_eq_approx(a, b):
         if type(a) is numpy.ndarray and type(b) is numpy.ndarray: