Optical physics does digital optimization—which we call Onsager Computing—for machine learning, control theory, backpropagation, etc.

Optimization is vital to Engineering, Artificial Intelligence, and to many areas of Science. Mathematically, we usually employ steepest-descent, or other digital algorithms. But, Physics itself, performs optimizations in the normal course of dynamical evolution. Nature provides us with the following optimization principles: 1. The Principle of Least Action; 2. The Variational Principle of Quantum Mechanics; 3. The Principle of Minimum Entropy Generation; 4. The First Mode to Threshold method; 5. The Principle of Least Time; 6. The Adiabatic Evolution method; 7. Quantum Annealing Of these physics principles, "Minimum Entropy Generation" in the form of bistable electrical or optical circuits is particularly adaptable toward offering digital Optimization. For example, we provide the electrical circuit which can address the challenging Ising problem. Since Onsager, 1930, introduced the Principle of Minimum Entropy Generation we call this Onsager Computing.