make the autocast work correctly when we change floatX during the execution

theano/tensor/__init__.py

@@ -3,10 +3,6 @@ __docformat__ = "restructuredtext en"
 
 from basic import *
 
-if config.floatX == 'float32':
-    # change the default casting behaviour for python floats to always cast to float32
-    autocast_float.dtypes = ('float32',)
-
 import opt
 import blas
 import xlogx

theano/tensor/basic.py

@@ -164,6 +164,9 @@ class NumpyAutocaster(object):
     def __init__(self, dtypes):
         self.dtypes = tuple(dtypes)
     def __call__(self, x):
+        # change the default casting behaviour for python floats to always cast to float32
+        if config.floatX == 'float32' and config.floatX in self.dtypes:
+            return theano._asarray(x, dtype='float32')
         for dtype in self.dtypes:
             x_ = theano._asarray(x, dtype=dtype)
             if numpy.all(x == x_):