test MRG random stream with device=cuda and target=cpu, shared variable +…

theano/gpuarray/rng_mrg.py

@@ -14,7 +14,7 @@ from theano.tensor import as_tensor_variable, get_vector_length
 from theano.scalar import int32 as int_t
 
 from .basic_ops import (GpuKernelBase, Kernel, infer_context_name,
-                        host_from_gpu, as_gpuarray_variable)
+                        GpuFromHost, host_from_gpu, as_gpuarray_variable)
 from .type import GpuArrayType, gpu_context_type
 from .fp16_help import write_w
 from .opt import register_opt, register_opt2
@@ -309,7 +309,9 @@ class GPUA_mrg_uniform(GpuKernelBase, mrg_uniform_base):
 @register_opt2([mrg_uniform], 'fast_compile')
 def local_gpua_mrg_graph(op, context_name, inputs, outputs):
     if (type(op) == mrg_uniform and
-            isinstance(inputs[0].type, GpuArrayType)):
+            isinstance(inputs[0].type, GpuArrayType) and
+            not isinstance(inputs[0].owner.op, GpuFromHost)
+        ):
         outs = GPUA_mrg_uniform.new(inputs[0],
                                     op.output_type.ndim,
                                     op.output_type.dtype,

theano/sandbox/tests/test_rng_mrg.py

@@ -11,7 +11,7 @@ from six.moves import xrange
 import theano
 from theano import change_flags, config, tensor
 from theano.sandbox import rng_mrg
-from theano.sandbox.rng_mrg import MRG_RandomStreams
+from theano.sandbox.rng_mrg import MRG_RandomStreams, mrg_uniform
 from theano.tests import unittest_tools as utt
 from theano.tests.unittest_tools import attr
 
@@ -760,6 +760,21 @@ def test_target_parameter():
     basic_target_parameter_test(srng.multinomial_wo_replacement(pvals=pvals.astype('float32'), target='cpu'))
 
 
+def test_cpu_target_with_shared_variable():
+    srng = MRG_RandomStreams()
+
+    x = theano.shared(np.random.rand(2,3).astype('float32'), name='x')
+    y = srng.uniform(x.shape, target='cpu')
+    y.name = 'y'
+    z = (x * y).sum()
+    z.name = 'z'
+
+    fz = theano.function([], z)
+
+    nodes = fz.maker.fgraph.toposort()
+    assert any([isinstance(node.op, mrg_uniform) for node in nodes])
+
+
 if __name__ == "__main__":
     rng = MRG_RandomStreams(np.random.randint(2147462579))
     print(theano.__file__)