Function choose_strategy 

pub fn choose_strategy(spec: &MatmulSpec, chip: &ChipKnobs) -> MatmulStrategy

Choose the program strategy from the recognized shape + chip — the compiler making the op-library’s call. Heuristic (calibrated to the measured 640³ crossover): BlockReuse only pays once each core owns a large enough output block that saved DRAM re-reads outweigh its reduced overlap; below that, Simple’s streaming overlap wins. per_core_out ≥ 64 tiles (an 8×8-tile per-core block) is the switch.