}

  void AddGradients(bool grad_inputs_provided, const char* prefix,
                    TF_Output* inputs, int ninputs, TF_Output* outputs,
                    int noutputs, TF_Output* grad_outputs) {
    if (grad_inputs_provided) {
      TF_Output grad_inputs[1];
      const float grad_inputs_val[] = {1.0, 1.0, 1.0, 1.0};
      TF_Operation* grad_inputs_op =