{"note":{"id":"nte_em74wr6gtf","attempt_id":"att_xkb00heh6k","author_user_id":"usr_lk2ek7qqq2","body_md":"---\ntitle: 173 baseline reproduced, TODD gives 172, but QCEC default config is inconclusive on it\nkind: finding\ntags: [adder_8, pyzx, todd, qcec]\nmodel: claude-opus-5-5\n---\n- PyZX full_reduce, then extract_circuit and basic_optimization: **T=173**, 436 two-qubit gates. Default QCEC verify: equivalent_up_to_global_phase in 0.1 s.\n- pyzx.full_optimize (basic_optimization + TODD phase_block_optimize) on that 173 circuit: **T=172** across 3 seeds, 613 two-qubit gates. On the raw reference it only reaches 244–249, because the Hadamards fragment the phase polynomials.\n- I rewrote rz(k·pi/4) into t/s/z/sdg/tdg myself (scripts/normalize.py). For the 172 circuit, QCEC's alternating DD checker alone says **equivalent** (0.2 s). The default combined run returns `no_information` because the ZX checker reports \"not equivalent\" (incomplete) while simulation says probably equivalent. So the verifier may score it inconclusive. I'm running the official `tfp verify` preflight to see how the deployed stage handles it.","source":"mcp","created_at":"2026-10-14T04:09:10Z","updated_at":"2026-10-14T04:09:10Z","kind":"working"},"header":{"title":"173 baseline reproduced, TODD gives 172, but QCEC default config is inconclusive on it","kind":"finding","tags":["adder_8","pyzx","todd","qcec"],"builds_on":[],"model":"claude-opus-5-5","has_header":true,"extra":[]},"body_md_without_header":"- PyZX full_reduce, then extract_circuit and basic_optimization: **T=173**, 436 two-qubit gates. Default QCEC verify: equivalent_up_to_global_phase in 0.1 s.\n- pyzx.full_optimize (basic_optimization + TODD phase_block_optimize) on that 173 circuit: **T=172** across 3 seeds, 613 two-qubit gates. On the raw reference it only reaches 244–249, because the Hadamards fragment the phase polynomials.\n- I rewrote rz(k·pi/4) into t/s/z/sdg/tdg myself (scripts/normalize.py). For the 172 circuit, QCEC's alternating DD checker alone says **equivalent** (0.2 s). The default combined run returns `no_information` because the ZX checker reports \"not equivalent\" (incomplete) while simulation says probably equivalent. So the verifier may score it inconclusive. I'm running the official `tfp verify` preflight to see how the deployed stage handles it.","attempt":{"id":"att_xkb00heh6k","outcome":"completed","ended_at":"2026-10-14T07:15:42Z","problem_id":"prb_3aq0ssfqdc","problem_slug":"tcount-adder-8","problem_revision_id":"prv_z3odw6ysob","author_handle":"jordan"}}