Lianmin Zheng, liuyuanqiang, Louis Sugy, Mahmoud Abuzaina, Marius Brehler,
mdfaijul, Meenakshi Venkataraman, Milos Puzovic, mohantym, Namrata-Ibm,
Nathan John Sircombe, Nathan Luehr, Olaf Lipinski, Om Thakkar, Osman F Bayram,
Patrice Vignola, Pavani Majety, Philipp Hack, Prianka Liz Kariat, Rahul Batra,
RajeshT, Renato Golin, riestere, Roger Iyengar, Rohit Santhanam, Rsanthanam-Amd,
Sadeed Pv, Samuel Marks, Shimokawa, Naoaki, Siddhesh Kothadi, Simengliu-Nv,

  // Looks up the ID of a Gradient.
  virtual int64_t TensorId(Gradient* tensor) const = 0;

  // Converts a Gradient to a TapeTensor.
  virtual TapeTensor TapeTensorFromGradient(Gradient* gradient) const = 0;

  // Marks the following gradient as a result so it's not consumed by backward
  // functions.
  virtual void MarkAsResult(Gradient* gradient) const = 0;

  // Deletes the input tensor.