Custom optimizersΒΆ

Evaluation of energy of iPEPS involves the computation of environment (CTM) which is typically the bottleneck of the optimization.

Currently, the reverse-mode differentiation of CTM relies on using full-rank decomposition when constructing the projectors. Using line search algorithms which do not rely on derivatives allows for truncated decomposition in CTM and leads to considerable speed-up. The following optimizers (based on their PyTorch parents) implement backtracking line search and provide support for specialized cost functions to be used within line search context.