Function BroadcastToGrad

tensorflow/cc/gradients/array_grad.cc:562–578

REGISTER_GRADIENT_OP("ConcatV2", ConcatV2Grad);

Status BroadcastToGrad(const Scope& scope, const Operation& op,
                       const std::vector<Output>& grad_inputs,
                       std::vector<Output>* grad_outputs) {
  if (grad_inputs.size() != 1) {
    return errors::InvalidArgument("BroadcastTo grad should have 1 grad input");
  }
  if (op.num_inputs() != 2) {
    return errors::InvalidArgument("BroadcastTo requires 2 inputs");
  }

  auto x_shape = Shape(scope, op.input(0));
  auto args = internal::BroadcastGradientArgs(scope, x_shape, op.input(1));
  auto sum_gx = Sum(scope, grad_inputs[0], args.r0);
  grad_outputs->push_back(Reshape(scope, sum_gx, x_shape));
  grad_outputs->push_back(NoGradient());
  return scope.status();
}

REGISTER_GRADIENT_OP("BroadcastTo", BroadcastToGrad);