einsum.readthedocs.io/en/stable/) to speed up computation or to
     consume less memory by optimizing contraction order. This
     optimization occurs when there are at least three inputs, since
     the order does not matter otherwise. Note that finding the
     optimal path is an NP-hard problem, thus, opt_einsum relies on
     different heuristics to achieve near-optimal results. If
     opt_einsum is not available, the default order is to contract
     from left to right.To bypass this default behavior, add the
     following line to disable the usage of opt_einsum and skip path
     calculation: torch.backends.opt_einsum.enabled = FalseTo
     specify which strategy you'd like for opt_einsum to compute the
     contraction path, add the following line:
     torch.backends.opt_einsum.strategy = 'auto'. The default
     strategy is 'auto', and we also support 'greedy' and 'optimal'.
     Disclaimer that the runtime of 'optimal' is factorial in the