What a Commercial PCB Placer Does That My Open-Source One Can't
I wrote an open-source simulated-annealing PCB placer to benchmark against Quilter, a commercial placement service. On a dense 161-net Arduino Giga shield, Quilter routed 99.4% of the board; my placer plateaued at 93.8%. Here is the full comparison, the numbers, and the specific class of signals that pyplacer couldn't get routed.