[GitHub] haojin2 commented on a change in pull request #11024: concat of CSR NDArrays on first dimension

[GitBox <gi...@apache.org>]

haojin2 commented on a change in pull request #11024: concat of CSR NDArrays on first dimension
URL: https://github.com/apache/incubator-mxnet/pull/11024#discussion_r192551908
 
 

 ##########
 File path: src/operator/nn/concat-inl.h
 ##########
 @@ -154,6 +154,82 @@ void ConcatGradCompute(const nnvm::NodeAttrs& attrs, const OpContext& ctx,
   });
 }
 
+
+struct concat_csr_first_dim {
+  // i is the i-th row of the output ndarray
+  template<typename DType, typename RType, typename IType>
+  MSHADOW_XINLINE static void Map(int i, const OpReqType req,
+                                  DType* out_data, const DType* in_data,
+                                  RType* out_indptr, const RType* in_indptr,
+                                  IType* out_idx, const IType* in_idx,
+                                  const nnvm::dim_t indptr_offset,
+                                  const nnvm::dim_t idx_offset) {
+    if (i == 0) out_indptr[0] = 0;
+    out_indptr[i+1+indptr_offset] = in_indptr[i+1] + idx_offset;
+    for (nnvm::dim_t j = in_indptr[i]; j < in_indptr[i+1]; ++j) {
+      KERNEL_ASSIGN(out_idx[j+idx_offset], req, in_idx[j]);
+      KERNEL_ASSIGN(out_data[j+idx_offset], req, in_data[j]);
+    }
+  }
+};
+
+
+
 
 Review comment:
   nit: too many blank lines here

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