Retain compatibility with CuDNN v2 (cuda backend)

theano/sandbox/cuda/cudnn_helper.h

@@ -3,6 +3,38 @@
 
 #include <cudnn.h>
 
+// If needed, define element of the V3 interface in terms of elements of
+// previous versions
+#if defined(CUDNN_VERSION) && CUDNN_VERSION < 3000
+
+// Starting in V3, the cudnnSetConvolutionNdDescriptor has an additional
+// parameter that determines the data type in which to do the computation.
+// For versions older than V3, we need to define an alias for that function
+// that will take the additional parameter as input but ignore it.
+static inline cudnnStatus_t cudnnSetConvolutionNdDescriptor_v3(
+                                        cudnnConvolutionDescriptor_t convDesc,
+                                        int arrayLength,
+                                        int padA[],
+                                        int filterStrideA[]
+                                        int upscaleA[],
+                                        cudnnConvolutionMode_t mode,
+                                        cudnn_dataType_t dataType)
+
+  return cudnnSetConvolutionNdDescriptor(convDesc, arrayLength, padA,
+                                         filterStrideA, upscaleA, mode);
+)
+
+#endif
+
+// If needed, define element of the V4 interface in terms of elements of
+// previous versions
+#if defined(CUDNN_VERSION) && CUDNN_VERSION < 4000
+
+#define CUDNN_CONVOLUTION_FWD_ALGO_FFT_TILING 5
+#define CUDNN_CONVOLUTION_BWD_DATA_ALGO_FFT_TILING 3
+
+#endif
+
 #ifndef CUDNN_VERSION
 #include <assert.h>
 

theano/sandbox/cuda/dnn.py

@@ -362,7 +362,7 @@ class GpuDnnConvDesc(GpuOp):
     }
   }
 
-  err = cudnnSetConvolutionNdDescriptor(
+  err = cudnnSetConvolutionNdDescriptor_v3(
   %(desc)s,
   %(nb_dim)d,
   pad, subsample, upscale,