add attr auto_grown_table

paddle/fluid/operators/lookup_sparse_table_op.cc

@@ -49,6 +49,7 @@ class LookupSparseTableOp : public framework::OperatorBase {
     unsigned int seed = static_cast<unsigned int>(Attr<int>("seed"));
     float min = Attr<float>("min");
     float max = Attr<float>("max");
+    bool auto_grown_table = Attr<bool>("auto_grown_table");
 
     PADDLE_ENFORCE(out_var->IsType<framework::LoDTensor>(),
                    "The type of Out var should be LodTensor.");
@@ -71,8 +72,11 @@ class LookupSparseTableOp : public framework::OperatorBase {
     PADDLE_ENFORCE_EQ(framework::ToDataType(w_t->value().type()),
                       framework::proto::VarType::FP32,
                       "The sparse table only support FP32");
-
     auto non_keys_pair = w_t->Get(keys, out_t);
+    if (!auto_grown_table) {
+      PADDLE_ENFORCE_EQ(non_keys_pair.size(), static_cast<size_t>(0),
+                        "there is some keys does exists in the sparse table.");
+    }
     auto value_shape = w_t->value().dims();
     value_shape[0] = 1;
     for (const auto &it : non_keys_pair) {
@@ -130,6 +134,10 @@ class LookupSparseTableOpMaker : public framework::OpProtoAndCheckerMaker {
                  "Note that if seed is not 0, this operator will always "
                  "generate the same random numbers every time.")
         .SetDefault(0);
+    AddAttr<bool>("auto_grown_table",
+                  "(bool default false)"
+                  "Whether create new value if for nonexistent key.")
+        .SetDefault(true);
     AddComment(R"DOC(
 Lookup Sprase Tablel Operator.