optimize code and comment

paddle/fluid/operators/merge_ids_op.cc

@@ -21,15 +21,17 @@ class MergeIdsOpMaker : public framework::OpProtoAndCheckerMaker {
  public:
   void Make() override {
     AddInput("Ids", "(LoDTensor) the input ids with shape{batch_num, 1}");
-    AddInput("X",
-             "(LoDTensor) the input tensor with shape{batch_num, N}, N is the "
-             "size of embedding table")
+    AddInput(
+        "X",
+        "(LoDTensors) multi input tensor with shape{batch_num, N}, N is the "
+        "size of embedding table")
         .AsDuplicable();
     AddOutput("Out", "(LoDTensor) The merged outputs of the input tensors.");
 
     AddComment(R"DOC(
 Merge multi LoDTensor's into one according to Ids's shard num.
-The values in the input LoDTensor are lookuped from the output of splite_ids_op
+The values in the input LoDTensor are lookuped from the output of split_ids_op
+
 Example:
   Input:
     Ids = [1,2,3,4,5,6]

paddle/fluid/operators/merge_ids_op.h

@@ -47,10 +47,10 @@ class MergeIdsOpKernel : public framework::OpKernel<T> {
     int batch_size = 0;
     int embedding_size = 0;
     for (auto &input : x_tensors) {
-      if (embedding_size == 0) {
-        embedding_size = input->dims()[1];
-      }
       if (framework::product(input->dims()) != 0) {
+        if (embedding_size == 0) {
+          embedding_size = input->dims()[1];
+        }
         PADDLE_ENFORCE_EQ(embedding_size, input->dims()[1],
                           "embedding size of all input should be the same");
         batch_size += input->dims()[0];
@@ -58,7 +58,7 @@ class MergeIdsOpKernel : public framework::OpKernel<T> {
     }
     PADDLE_ENFORCE_EQ(
         batch_size, ids_dims[0],
-        "the batch size of ids and embedding value should be the same");
+        "the batch size of ids and merged embedding value should be the same");
 
     const size_t shard_num = x_tensors.size();
 
@@ -80,7 +80,7 @@ class MergeIdsOpKernel : public framework::OpKernel<T> {
         in_indexs[shard_id] += 1;
       }
 
-      for (int i = 0; i < shard_num; ++i) {
+      for (size_t i = 0; i < shard_num; ++i) {
         PADDLE_ENFORCE_EQ(in_indexs[i], x_tensors[i]->dims()[0],
                           "after merge, all data in x_tensor should be used");
       }