GpuCorrMM (gpuarray) with zero-sized inputs, channels, filters.

theano/gpuarray/blas.py

@@ -528,7 +528,7 @@ class BaseGpuCorrMM(CGpuKernelBase):
 
     def c_code_cache_version(self):
         # Raise this whenever modifying the code below.
-        return (6,)
+        return (7,)
 
     def c_code_helper(self, bottom, weights, top, direction, sub, height=None, width=None):
         """
@@ -1125,7 +1125,7 @@ class BaseGpuCorr3dMM(CGpuKernelBase):
 
     def c_code_cache_version(self):
         # raise this whenever modifying the code below.
-        return (6,)
+        return (7,)
 
     def c_code_helper(self, bottom, weights, top, direction, sub,
                       height=None, width=None, depth=None):

theano/gpuarray/corr3d_gemm.c

@@ -487,6 +487,17 @@ PyGpuArrayObject* corr3dMM(PyGpuArrayObject *const bottom,
     PyGpuArrayObject *output;
     if (direction == 0) {  // forward pass
         output = top;
+        if (batchSize == 0 || nChannels == 0 || nFilters == 0) {
+            err = GpuArray_memset(&output->ga, 0);
+            if (err != GA_NO_ERROR) {
+                PyErr_Format(PyExc_RuntimeError,
+                             "GpuCorr3dMM could not fill the output with zeros: %d", err);
+                Py_DECREF(col);
+                return NULL;
+            }
+            Py_DECREF(col);
+            return output;
+        }
         // valid correlation: im3d2col, then gemm
         // Iterate over batch
         for (size_t n = 0; n < batchSize; n++) {
@@ -538,6 +549,17 @@ PyGpuArrayObject* corr3dMM(PyGpuArrayObject *const bottom,
     }
     else if (direction == 1) {  // backprop wrt. weights
         output = weight;
+        if (batchSize == 0 || nChannels == 0 || nFilters == 0) {
+            err = GpuArray_memset(&output->ga, 0);
+            if (err != GA_NO_ERROR) {
+                PyErr_Format(PyExc_RuntimeError,
+                             "GpuCorr3dMM grad wrt. weights could not fill the output with zeros: %d", err);
+                Py_DECREF(col);
+                return NULL;
+            }
+            Py_DECREF(col);
+            return output;
+        }
         // valid convolution: im3col, then gemm
         // Iterate over batch
         for (size_t n = 0; n < batchSize; n++) {
@@ -589,9 +611,29 @@ PyGpuArrayObject* corr3dMM(PyGpuArrayObject *const bottom,
                 return NULL;
             }
         }
+        if (batchSize == 0) {
+            err = GpuArray_memset(&weight->ga, 0);
+            if (err != GA_NO_ERROR) {
+                PyErr_Format(PyExc_RuntimeError,
+                             "GpuCorr3dMM grad weights could not fill the output with zeros: %d", err);
+                Py_DECREF(col);
+                return NULL;
+            }
+        }
     }
     else if (direction == 2) {  // backprop wrt. inputs
         output = bottom;
+        if (batchSize == 0 || nChannels == 0 || nFilters == 0) {
+            err = GpuArray_memset(&output->ga, 0);
+            if (err != GA_NO_ERROR) {
+                PyErr_Format(PyExc_RuntimeError,
+                             "GpuCorr3dMM grad wrt. inputs could not fill the output with zeros: %d", err);
+                Py_DECREF(col);
+                return NULL;
+            }
+            Py_DECREF(col);
+            return output;
+        }
         // full convolution: gemm, then col2im3d
         // Iterate over batch
         for (size_t n = 0; n < batchSize; n++) {

theano/gpuarray/corr_gemm.c

@@ -418,6 +418,17 @@ PyGpuArrayObject* corrMM(PyGpuArrayObject *const bottom,
     PyGpuArrayObject *output;
     if (direction == 0) {  // forward pass
         output = top;
+        if (batchSize == 0 || nChannels == 0 || nFilters == 0) {
+            err = GpuArray_memset(&output->ga, 0);
+            if (err != GA_NO_ERROR) {
+                PyErr_Format(PyExc_RuntimeError,
+                             "GpuCorrMM could not fill the output with zeros: %d", err);
+                Py_DECREF(col);
+                return NULL;
+            }
+            Py_DECREF(col);
+            return output;
+        }
         // valid correlation: im2col, then gemm
         // Iterate over batch
         for (size_t n = 0; n < batchSize; n++) {
@@ -469,6 +480,17 @@ PyGpuArrayObject* corrMM(PyGpuArrayObject *const bottom,
     }
     else if (direction == 1) {  // backprop wrt. weights
         output = weight;
+        if (batchSize == 0 || nChannels == 0 || nFilters == 0) {
+            err = GpuArray_memset(&output->ga, 0);
+            if (err != GA_NO_ERROR) {
+                PyErr_Format(PyExc_RuntimeError,
+                             "GpuCorrMM grad wrt. weights could not fill the output with zeros: %d", err);
+                Py_DECREF(col);
+                return NULL;
+            }
+            Py_DECREF(col);
+            return output;
+        }
         // valid convolution: im2col, then gemm
         // Iterate over batch
         for (size_t n = 0; n < batchSize; n++) {
@@ -523,6 +545,17 @@ PyGpuArrayObject* corrMM(PyGpuArrayObject *const bottom,
     }
     else if (direction == 2) {  // backprop wrt. inputs
         output = bottom;
+        if (batchSize == 0 || nChannels == 0 || nFilters == 0) {
+            err = GpuArray_memset(&output->ga, 0);
+            if (err != GA_NO_ERROR) {
+                PyErr_Format(PyExc_RuntimeError,
+                             "GpuCorrMM grad wrt. inputs could not fill the output with zeros: %d", err);
+                Py_DECREF(col);
+                return NULL;
+            }
+            Py_DECREF(col);
+            return output;
+        }
         // full convolution: gemm, then col2im
         // Iterate over batch
         for (size_t n = 0; n < batchSize; n++) {