add support for grouped convolution in GpuCorrMM

theano/gpuarray/blas.py

@@ -489,11 +489,11 @@ class BaseGpuCorrMM(CGpuKernelBase):
         Perform subsampling of the input, also known as dilation (default: (1, 1)).
     """
     check_broadcast = False
-    __props__ = ('border_mode', 'subsample', 'filter_dilation')
+    __props__ = ('border_mode', 'subsample', 'filter_dilation', 'num_groups')
     _f16_ok = True
 
     def __init__(self, border_mode="valid", subsample=(1, 1),
-                 filter_dilation=(1, 1)):
+                 filter_dilation=(1, 1), num_groups=1):
         if isinstance(border_mode, integer_types):
             border_mode = (border_mode, border_mode)
         if isinstance(border_mode, tuple):
@@ -512,6 +512,9 @@ class BaseGpuCorrMM(CGpuKernelBase):
             raise ValueError("filter_dilation must have two elements")
         self.subsample = tuple(subsample)
         self.filter_dilation = tuple(filter_dilation)
+        if num_groups < 1:
+            raise ValueError("Number of groups should be greater than 0")
+        self.num_groups = num_groups
         CGpuKernelBase.__init__(self, ['corr_gemm.c'])
 
     @property
@@ -521,11 +524,12 @@ class BaseGpuCorrMM(CGpuKernelBase):
         return (0, 0)
 
     def __str__(self):
-        return '%s{%s, %s, %s}' % (
+        return '%s{%s, %s, %s, %s}' % (
             self.__class__.__name__,
             self.border_mode,
             str(self.subsample),
-            str(self.filter_dilation))
+            str(self.filter_dilation),
+            str(self.num_groups))
 
     def flops(self, inp, outp):
         """
@@ -600,6 +604,7 @@ class BaseGpuCorrMM(CGpuKernelBase):
         """
         dH, dW = self.subsample
         dilH, dilW = self.filter_dilation
+        numgroups = self.num_groups
         if self.border_mode == "half":
             padH = padW = -1
         elif self.border_mode == "full":
@@ -660,6 +665,7 @@ class BaseGpuCorrMM(CGpuKernelBase):
     size_t dilW = %(dilW)s;
     int padH = %(padH)s;
     int padW = %(padW)s;
+    int numgroups = %(numgroups)s;
 
     PyGpuArrayObject * bottom = %(bottom)s;
     PyGpuArrayObject * weights = %(weights)s;
@@ -759,7 +765,7 @@ class BaseGpuCorrMM(CGpuKernelBase):
         // output is weights: (num_filters, num_channels, height, width)
         // height and width: weights = (bottom + 2*pad - (top - 1) * sample - 1) / dil + 1
         out_dim[0] = PyGpuArray_DIMS(top)[1];
-        out_dim[1] = PyGpuArray_DIMS(bottom)[1];
+        out_dim[1] = PyGpuArray_DIMS(bottom)[1] / numgroups;
         out_dim[2] = kH;  // already inferred further above
         out_dim[3] = kW;  // how convenient
         out_typecode = top->ga.typecode;
@@ -783,7 +789,7 @@ class BaseGpuCorrMM(CGpuKernelBase):
         // output is bottom: (batchsize, num_channels, height, width)
         // height and width: bottom = (top - 1) * sample + (weights-1)*dil + 1 - 2*pad
         out_dim[0] = PyGpuArray_DIMS(top)[0];
-        out_dim[1] = PyGpuArray_DIMS(weights)[1];
+        out_dim[1] = PyGpuArray_DIMS(weights)[1] * numgroups;
         out_dim[2] = (%(height)s != -1) ? %(height)s : (PyGpuArray_DIMS(top)[2] - 1) * dH + (PyGpuArray_DIMS(weights)[2]-1)*dilH + 1 - 2*padH;
         out_dim[3] = (%(width)s != -1) ? %(width)s : (PyGpuArray_DIMS(top)[3] - 1) * dW + (PyGpuArray_DIMS(weights)[3]-1)*dilW + 1 - 2*padW;
         out_typecode = top->ga.typecode;
@@ -827,7 +833,7 @@ class BaseGpuCorrMM(CGpuKernelBase):
     }
 
     // Call GPU code
-    out2 = corrMM(%(bottom)s, %(weights)s, %(top)s, direction, dH, dW, dilH, dilW, padH, padW);
+    out2 = corrMM(%(bottom)s, %(weights)s, %(top)s, direction, dH, dW, dilH, dilW, padH, padW, numgroups);
     if (out2==NULL){
        %(fail)s
     }
@@ -883,9 +889,9 @@ class GpuCorrMM(BaseGpuCorrMM):
     """
     def __init__(self, border_mode="valid",
                  subsample=(1, 1),
-                 filter_dilation=(1, 1)):
+                 filter_dilation=(1, 1), num_groups=1):
         super(GpuCorrMM, self).__init__(border_mode, subsample,
-                                        filter_dilation)
+                                        filter_dilation, num_groups)
 
     def make_node(self, img, kern):
         ctx_name = infer_context_name(img, kern)
@@ -914,11 +920,13 @@ class GpuCorrMM(BaseGpuCorrMM):
         top = gpu_contiguous(top)
         d_bottom = GpuCorrMM_gradInputs(self.border_mode,
                                         self.subsample,
-                                        self.filter_dilation)(
+                                        self.filter_dilation,
+                                        self.num_groups)(
             weights, top, bottom.shape[-2:])
         d_weights = GpuCorrMM_gradWeights(self.border_mode,
                                           self.subsample,
-                                          self.filter_dilation)(
+                                          self.filter_dilation,
+                                          self.num_groups)(
             bottom, top, weights.shape[-2:])
         return d_bottom, d_weights
 
@@ -936,10 +944,11 @@ class GpuCorrMM_gradWeights(BaseGpuCorrMM):
 
     def __init__(self, border_mode="valid",
                  subsample=(1, 1),
-                 filter_dilation=(1, 1)):
+                 filter_dilation=(1, 1),
+                 num_groups=1):
         super(GpuCorrMM_gradWeights, self).__init__(border_mode,
                                                     subsample,
-                                                    filter_dilation)
+                                                    filter_dilation, num_groups)
 
     def make_node(self, img, topgrad, shape=None):
         ctx_name = infer_context_name(img, topgrad)
@@ -978,11 +987,12 @@ class GpuCorrMM_gradWeights(BaseGpuCorrMM):
         weights = gpu_contiguous(weights)
         d_bottom = GpuCorrMM_gradInputs(self.border_mode,
                                         self.subsample,
-                                        self.filter_dilation)(weights,
+                                        self.filter_dilation,
+                                        self.num_groups)(weights,
                                                          top,
                                                          bottom.shape[-2:])
         d_top = GpuCorrMM(
-            self.border_mode, self.subsample, self.filter_dilation)(bottom, weights)
+            self.border_mode, self.subsample, self.filter_dilation, self.num_groups)(bottom, weights)
         d_height_width = (
             theano.gradient.DisconnectedType()(),
             ) * 2 if len(inp) == 4 else ()
@@ -1008,9 +1018,10 @@ class GpuCorrMM_gradInputs(BaseGpuCorrMM):
 
     def __init__(self, border_mode="valid",
                  subsample=(1, 1),
-                 filter_dilation=(1, 1)):
+                 filter_dilation=(1, 1),
+                 num_groups=1):
         super(GpuCorrMM_gradInputs, self).__init__(border_mode, subsample,
-                                                   filter_dilation)
+                                                   filter_dilation, num_groups)
 
     def make_node(self, kern, topgrad, shape=None):
         ctx_name = infer_context_name(kern, topgrad)
@@ -1029,6 +1040,10 @@ class GpuCorrMM_gradInputs(BaseGpuCorrMM):
             assert shape[0].ndim == 0
             assert shape[1].ndim == 0
 
+        if self.num_groups > 1:
+            broadcastable = [topgrad.type.broadcastable[0], False,
+                             False, False]
+        else:
             broadcastable = [topgrad.type.broadcastable[0], kern.type.broadcastable[1],
                              False, False]
         return Apply(self, [kern, topgrad] + height_width, [GpuArrayType(dtype=topgrad.dtype,
@@ -1048,12 +1063,14 @@ class GpuCorrMM_gradInputs(BaseGpuCorrMM):
         bottom = gpu_contiguous(bottom)
         d_weights = GpuCorrMM_gradWeights(self.border_mode,
                                           self.subsample,
-                                          self.filter_dilation)(bottom,
+                                          self.filter_dilation,
+                                          self.num_groups)(bottom,
                                                            top,
                                                            weights.shape[-2:])
         d_top = GpuCorrMM(self.border_mode,
                           self.subsample,
-                          self.filter_dilation)(bottom, weights)
+                          self.filter_dilation,
+                          self.num_groups)(bottom, weights)
         d_height_width = (
             theano.gradient.DisconnectedType()(),
             ) * 2 if len(inp) == 4 else ()

theano/gpuarray/corr_gemm.c

@@ -348,7 +348,8 @@ PyGpuArrayObject* corrMM(PyGpuArrayObject *const bottom,
                          const size_t dilH = 1,
                          const size_t dilW = 1,
                          const size_t padH = 0,
-                         const size_t padW = 0)
+                         const size_t padW = 0,
+                         const size_t numgroups = 1)
 {
     if (PyGpuArray_NDIM(bottom) != 4)
     {
@@ -411,8 +412,8 @@ PyGpuArrayObject* corrMM(PyGpuArrayObject *const bottom,
     const size_t nFilters = PyGpuArray_DIMS(weight)[0];
     const size_t kH = PyGpuArray_DIMS(weight)[2];
     const size_t kW = PyGpuArray_DIMS(weight)[3];
-    if (nChannels != PyGpuArray_DIMS(weight)[1]) {
-        PyErr_SetString(PyExc_ValueError,
+    if (nChannels != (PyGpuArray_DIMS(weight)[1] * numgroups)) {
+        PyErr_Format(PyExc_ValueError,
                 "GpuCorrMM images and kernel must have the same stack size\n");
         return NULL;
     }
@@ -469,11 +470,15 @@ PyGpuArrayObject* corrMM(PyGpuArrayObject *const bottom,
     }
 
     // Define some useful variables
-    const size_t bottom_stride = PyGpuArray_STRIDES(bottom)[0] / gpuarray_get_elsize(bottom->ga.typecode);
-    const size_t top_stride = PyGpuArray_STRIDES(top)[0] / gpuarray_get_elsize(top->ga.typecode);
-    const size_t K_ = col_dim[0];
+    const size_t batch_bottom_stride = PyGpuArray_STRIDES(bottom)[0] / gpuarray_get_elsize(bottom->ga.typecode);
+    const size_t batch_top_stride = PyGpuArray_STRIDES(top)[0] / gpuarray_get_elsize(top->ga.typecode);
+    const size_t group_bottom_stride = (PyGpuArray_STRIDES(bottom)[1] * nChannels / numgroups) / gpuarray_get_elsize(bottom->ga.typecode);
+    const size_t group_top_stride = (PyGpuArray_STRIDES(top)[1] * nFilters / numgroups) / gpuarray_get_elsize(top->ga.typecode);
+    const size_t group_weight_stride = (PyGpuArray_STRIDES(weight)[0] * nFilters / numgroups) / gpuarray_get_elsize(weight->ga.typecode);
+    const size_t K_ = col_dim[0] / numgroups;
     const size_t N_ = col_dim[1];
-    const size_t M_ = nFilters;
+    const size_t group_col_stride = (K_ * N_);
+    const size_t M_ = nFilters / numgroups;
 
     PyGpuArrayObject *output;
     if (direction == 0) {  // forward pass
@@ -493,7 +498,7 @@ PyGpuArrayObject* corrMM(PyGpuArrayObject *const bottom,
         // Iterate over batch
         for (size_t n = 0; n < batchSize; n++) {
             // First, im2col
-	  err = im2col(&bottom->ga, n * bottom_stride,
+            err = im2col(&bottom->ga, n * batch_bottom_stride,
                          nChannels, bottomHeight,
                          bottomWidth, kH, kW, dilH, dilW,
                          padH, padW, dH, dW, &col->ga);
@@ -502,12 +507,14 @@ PyGpuArrayObject* corrMM(PyGpuArrayObject *const bottom,
                 return NULL;
             }
             // Second, gemm
+            for (size_t g = 0; g < numgroups; g++){
                 err = rgemm(cb_fortran, cb_no_trans, cb_no_trans,
                             N_, M_, K_, 1,
-                        &col->ga, 0, N_,
-                        &weight->ga, 0, K_,
+                            &col->ga, g * group_col_stride, N_,
+                            &weight->ga, g * group_weight_stride, K_,
                             0,
-                        &top->ga, n * top_stride, N_);
+                            &top->ga, n * batch_top_stride + g * group_top_stride, N_);
+            }
             if (err != GA_NO_ERROR) {
                 PyErr_Format(PyExc_RuntimeError,
                              "GpuCorrMM forward encountered an error running gemm: %d", err);
@@ -533,7 +540,7 @@ PyGpuArrayObject* corrMM(PyGpuArrayObject *const bottom,
         // Iterate over batch
         for (size_t n = 0; n < batchSize; n++) {
             // First, im2col
-            err = im2col(&bottom->ga, n * bottom_stride,
+            err = im2col(&bottom->ga, n * batch_bottom_stride,
                          nChannels, bottomHeight,
                          bottomWidth, kH, kW, dilH, dilW,
                          padH, padW, dH, dW, &col->ga);
@@ -545,12 +552,14 @@ PyGpuArrayObject* corrMM(PyGpuArrayObject *const bottom,
             // Note that we accumulate into weight. We do so by setting beta = 0
             // for the first iteration and beta = 1 for subsequent ones. (This
             // is faster than setting weight to all zeros before the loop.)
+            for(size_t g = 0; g < numgroups; g++){ 
                 err = rgemm(cb_fortran, cb_trans, cb_no_trans,
                             K_, M_, N_, 1,
-                        &col->ga, 0, N_,
-                        &top->ga, n * top_stride, N_,
+                            &col->ga, g * group_col_stride, N_,
+                            &top->ga, n * batch_top_stride + g * group_top_stride, N_,
                             (n == 0) ? 0 : 1,
-                        &weight->ga, 0, K_);
+                            &weight->ga, g * group_weight_stride, K_);
+            }
             if (err != GA_NO_ERROR) {
                 PyErr_Format(PyExc_RuntimeError,
                              "GpuCorrMM grad weights encountered an error running gemm: %d", err);
@@ -576,12 +585,14 @@ PyGpuArrayObject* corrMM(PyGpuArrayObject *const bottom,
         // Iterate over batch
         for (size_t n = 0; n < batchSize; n++) {
             // gemm into columns
+            for(size_t g = 0; g < numgroups; g++){
               err = rgemm(cb_fortran, cb_no_trans, cb_trans,
                           N_, K_, M_, 1,
-                      &top->ga, n * top_stride, N_,
-                      &weight->ga, 0, K_,
+                          &top->ga, n * batch_top_stride + g * group_top_stride, N_,
+                          &weight->ga, g * group_weight_stride, K_,
                           0,
-                      &col->ga, 0, N_);
+                          &col->ga, g * group_col_stride, N_);
+            }
             if (err != GA_NO_ERROR) {
                 PyErr_Format(PyExc_RuntimeError,
                              "GpuCorrMM grad inputs encountered an error running gemm: %d", err);
@@ -591,7 +602,7 @@ PyGpuArrayObject* corrMM(PyGpuArrayObject *const bottom,
             // col2im back to the data
             err = col2im(&col->ga, nChannels, bottomHeight, bottomWidth,
                          kH, kW, dilH, dilW, padH, padW,
-                         dH, dW, &bottom->ga, n * bottom_stride);
+                         dH, dW, &bottom->ga, n * batch_bottom_stride);
             if (err != GA_NO_ERROR) {
                 Py_DECREF(col);
                 return NULL;

theano/gpuarray/opt.py

@@ -1509,7 +1509,8 @@ def local_abstractconv_gemm(node):
     border_mode = node.op.border_mode
     subsample = node.op.subsample
     filter_dilation = node.op.filter_dilation
-    if ((border_mode == 'full') and (subsample == (1, 1))):
+
+    if ((border_mode == 'full') and (subsample == (1, 1)) and node.op.num_groups == 1):
         if not node.op.filter_flip:
             kern = kern[:, :, ::-1, ::-1]
         # need to dimshuffle the kernel for full convolution
@@ -1526,7 +1527,8 @@ def local_abstractconv_gemm(node):
         # By default use GpuCorrMM
         rval = GpuCorrMM(border_mode,
                          subsample,
-                         filter_dilation)(gpu_contiguous(img),
+                         filter_dilation,
+                         node.op.num_groups)(gpu_contiguous(img),
                                              gpu_contiguous(kern))
 
         # call GpuCorrMM_gradWeights if good
@@ -1645,7 +1647,8 @@ def local_abstractconv_gradweights_gemm(node):
 
     rval = GpuCorrMM_gradWeights(border_mode=node.op.border_mode,
                                  subsample=node.op.subsample,
-                                 filter_dilation=node.op.filter_dilation)(
+                                 filter_dilation=node.op.filter_dilation,
+                                 num_groups=node.op.num_groups)(
         gpu_contiguous(img), gpu_contiguous(topgrad), shape)
     if node.op.filter_flip:
         rval = rval[:, :, ::-1, ::-1]
@@ -1689,7 +1692,8 @@ def local_abstractconv_gradinputs_gemm(node):
 
     rval = GpuCorrMM_gradInputs(border_mode=node.op.border_mode,
                                 subsample=node.op.subsample,
-                                filter_dilation=node.op.filter_dilation)(
+                                filter_dilation=node.op.filter_dilation,
+                                num_groups=node.op.num_groups)(
         gpu_contiguous(kern), gpu_contiguous(topgrad), shape)
     return [rval]