Benchmarks

The benchmark scripts live in benches/ and need the bench dependency group. Each folder's README holds the full tables and the commands to reproduce them.

PrimitivesCopy Anchor Link

benches/primitives compares the MPO-MPO product against quimb's contract-then-compress on the Leonardo supercomputer at CINECA. One MPO is random, the other a slightly perturbed identity, so the product is highly compressible.

At $\chi = 1000$, SRC also used about a sixth of the peak memory of quimb.

StacksCopy Anchor Link

benches/stack compares one sweep over a stack, src(A_1, ..., A_k, psi), with pairwise application truncating after every product, as a function of the number of trains.

• One sweep over the whole stack is at best moderately more accurate. For random stacks ending in an MPS it has about 20 % lower median error at depth 4; for random MPO products the gain is at most 8 %; for Trotter layers there is no systematic difference.
• Both methods sit 2-15x above the best possible error at the same bond dimension, so the randomized sketch, not compounding across layers, dominates the error.
• The per-site cost grows with $\chi^2$ times the product of the layer bonds. Thin Trotter layers run at 0.6-1.4x the pairwise time up to depth 5, while random MPOs of bond 8 and 16 at depth 4 are 30x and 136x slower.