Fix CorrMM for zero-sized inputs (avoid sgemm errors).

theano/tensor/nnet/corr.py

@@ -123,7 +123,7 @@ class BaseCorrMM(gof.OpenMPOp):
 
     def c_code_cache_version(self):
         # raise this whenever modifying any of the support_code_files
-        return (4, self.openmp, blas_header_version())
+        return (5, self.openmp, blas_header_version())
 
     def c_support_code_apply(self, node, nodename):
         # REMEMBER TO RAISE c_code_cache_version when changing any of

theano/tensor/nnet/corr3d.py

@@ -123,7 +123,7 @@ class BaseCorr3dMM(gof.OpenMPOp):
 
     def c_code_cache_version(self):
         # raise this whenever modifying any of the support_code_files
-        return (4, self.openmp, blas_header_version())
+        return (5, self.openmp, blas_header_version())
 
     def c_support_code_apply(self, node, nodename):
         # REMEMBER TO RAISE c_code_cache_version when changing any of

theano/tensor/nnet/corr3d_gemm.c

@@ -253,7 +253,23 @@ PyArrayObject* corr3dMM(PyArrayObject* bottom,
     char Trans = 'T';
     PyArrayObject *output;
 
-    if (direction == 0) {  // forward pass
+    if (batchSize == 0 || nChannels == 0 || nFilters == 0) {
+        switch(direction) {
+        case 0:
+            output = top;
+            break;
+        case 1:
+            output = weight;
+            break;
+        case 2:
+            output = bottom;
+            break;
+        default:
+            return NULL;
+        }
+        PyArray_FILLWBYTE(output, 0);
+    }
+    else if (direction == 0) {  // forward pass
         output = top;
         // valid correlation: im3d2col, then gemm
         // Iterate over batch

theano/tensor/nnet/corr_gemm.c

@@ -226,7 +226,23 @@ PyArrayObject* corrMM(PyArrayObject* bottom,
     char Trans = 'T';
     PyArrayObject *output;
 
-    if (direction == 0) {  // forward pass
+    if (batchSize == 0 || nChannels == 0 || nFilters == 0) {
+        switch(direction) {
+        case 0:
+            output = top;
+            break;
+        case 1:
+            output = weight;
+            break;
+        case 2:
+            output = bottom;
+            break;
+        default:
+            return NULL;
+        }
+        PyArray_FILLWBYTE(output, 0);
+    }
+    else if (direction == 0) {  // forward pass
         output = top;
         // valid correlation: im2col, then gemm
         // Iterate over batch