Ordering algorithms: "Tamaki solver is unavailable"

[danlkv]

Here's a question: "I get warnings: “QuickBB solver is unavailable” and “Tamaki solver is unavailable” — would installing them make the simulation run faster?"

[danlkv]

Tamaki and QuickBB are big boys for optimization, they work well if you allow running for several seconds to minutes. Use these if you need to run huge circuits, but note that for QAOA energy simulations you will need to run ordering algorithm num_edges times . Tamaki is currently the best algorithm, and it requires java. Here's how to install it: https://github.com/danlkv/QTensor#instalation.

If you need something in between tamaki and greedy algorithm, use rgreedy. It is a randomized ordering algorithm that repetitively runs greedy search with noise. More details on it here: https://arxiv.org/pdf/2012.02430.pdf section 5.1.2. The format for it is "rgreedy_tau_q", for example "rgreedy_0.02_10" will run 10x longer than greedy algorithm.

Here's a comparison between different ordering algos: https://github.com/danlkv/QTensor/blob/dev/analysis/spec/notebooks/QAOA_bench.ipynb section "Compare orderers"