support trainconfig and modelconfig of MergedModel

paddle/capi/gradient_machine.cpp

@@ -64,12 +64,18 @@ paddle_error paddle_gradient_machine_create_for_inference_with_parameters(
   modelConfigProtobuf.resize(modelConfigSize);
   is.read(&modelConfigProtobuf[0], modelConfigSize);
   paddle::TrainerConfig config;
+  paddle::ModelConfig modelConfig;
   if (!config.ParseFromString(modelConfigProtobuf) || !config.IsInitialized()) {
-    return kPD_PROTOBUF_ERROR;
+    if (!modelConfig.ParseFromString(modelConfigProtobuf) ||
+        !modelConfig.IsInitialized()) {
+      return kPD_PROTOBUF_ERROR;
+    }
+  } else {
+    modelConfig = config.model_config();
   }
   auto ptr = new paddle::capi::CGradientMachine();
   ptr->machine.reset(paddle::GradientMachine::create(
-      config.model_config(), CREATE_MODE_TESTING, {paddle::PARAMETER_VALUE}));
+      modelConfig, CREATE_MODE_TESTING, {paddle::PARAMETER_VALUE}));
   std::vector<paddle::ParameterPtr>& parameters = ptr->machine->getParameters();
   for (auto& para : parameters) {
     para->load(is);