make theano.sandbox.cuda import work when there is no pycuda or scikits.cuda

theano/sandbox/cuda/fftconv.py

@@ -6,17 +6,20 @@ import theano.tensor as T
 
 from theano.sandbox.cuda import (GpuOp, basic_ops, CudaNdarrayType,
                                  CudaNdarray)
-
-import scikits.cuda
-from scikits.cuda import fft, cublas, misc
-
-import pycuda.gpuarray
-
 import theano.misc.pycuda_init
+from theano.misc.pycuda_init import pycuda_available
+if pycuda_available:
+    import pycuda.gpuarray
+
+try:
+    import scikits.cuda
+    from scikits.cuda import fft, cublas
+    scikits.cuda.misc.init()
+    scikits_cuda_available = True
+except ImportError:
+    scikits_cuda_available = False
 
 
-misc.init()
-
 # TODO: investigate the effect of enabling fastmath on FFT performance
 # (how can it be enabled?).