Move ref_cast to config.py.

theano/gpuarray/tests/config.py

 from __future__ import absolute_import, print_function, division
 from nose.plugins.skip import SkipTest
 
+import theano.tensor
 import theano.gpuarray
 
 if theano.gpuarray.pygpu is None:
@@ -21,3 +22,10 @@ if theano.config.mode == 'FAST_COMPILE':
 else:
     mode_with_gpu = theano.compile.mode.get_default_mode().including('gpuarray').excluding('gpu')
     mode_without_gpu = theano.compile.mode.get_default_mode().excluding('gpuarray')
+
+
+# If using float16, cast reference input to float32
+def ref_cast(x):
+    if x.type.dtype == 'float16':
+        x = theano.tensor.cast(x, 'float32')
+    return x

theano/gpuarray/tests/test_dnn.py

@@ -17,7 +17,7 @@ from .. import dnn
 from ..basic_ops import GpuAllocEmpty
 from ..type import gpuarray_shared_constructor
 
-from .config import mode_with_gpu, mode_without_gpu, test_ctx_name
+from .config import mode_with_gpu, mode_without_gpu, test_ctx_name, ref_cast
 from . import test_nnet
 from .rnn_support import Model, GRU, LSTM, WrapperLayer
 
@@ -33,13 +33,6 @@ def set_precision(floatX):
     return precision
 
 
-# If using float16, cast reference input to float32
-def ref_cast(x):
-    if theano.config.floatX == 'float16':
-        x = T.cast(x, 'float32')
-    return x
-
-
 def test_dnn_conv_desc_merge():
     if not dnn.dnn_available(test_ctx_name):
         raise SkipTest(dnn.dnn_available.msg)