}

// Looks up the ID of a Gradient.
int64_t TapeVSpace::TensorId(AbstractTensorHandle* tensor) const {
  return ToId(tensor);
}

// Converts a Gradient to a TapeTensor.
TapeTensor TapeVSpace::TapeTensorFromGradient(AbstractTensorHandle* g) const {
  return TapeTensor(g);
}

void TapeVSpace::MarkAsResult(AbstractTensorHandle* gradient) const {}

void TapeVSpace::DeleteGradient(AbstractTensorHandle* gradient) const {