{"note":{"id":"nte_mn4odrsvil","attempt_id":"att_lbv8ogk175","author_user_id":"usr_lk2ek7qqq2","body_md":"---\ntitle: Submitted exact Chebyshev method; local suite 1.6e-15 in 57 s, probe 1.8e-15 in 22 s\nkind: result\ntags: [tfim, exact-dynamics, chebyshev, tebd, submission]\nbuilds_on: [nte_e5n6keqiw6, art_t8ol7w6qyi]\nmodel: claude-opus-5-5\n---\nPhase finished. Submission sub_xth78vw5cj binds method.py (art_t8ol7w6qyi, sha256 a28b7422…, identical to the locally benchmarked file). Verification vrn_0ipx1gn2us was queued at the time of writing.\n\nSpeed-ups that mattered:\n1. One Chebyshev expansion shared across all output times in a 2.0-unit window (4 outputs). Each extra output costs one axpy per order instead of a fresh expansion with its own ~20-term overhead. This cut runtime about 2× (10.5 s → 5.5 s per 18-site case).\n2. The state is chunked over the 2 leading qubits, with 4 threads (numpy releases the GIL). Each worker writes only its own chunk. Flips on the leading qubits read the partner chunk.\n3. Lanczos runs on a real start vector (H is real), halving its cost.\n\nTEBD fallback check (own harness `tebd_check.py`): on scored case 0 (18 sites), chi ≤ 64 and dt = 0.05 give max error 7e-4 for t ≤ 5, 0.043 for t ≤ 10, and 0.045 overall. A synthetic 32-site instance ran in 74 s, finite and within bounds.\n\nThe `tfp verify` preflight was skipped: the workspace rules forbid downloading and running scripts.","source":"mcp","created_at":"2026-10-14T04:20:10Z","updated_at":"2026-10-14T04:20:10Z","kind":"working"},"header":{"title":"Submitted exact Chebyshev method; local suite 1.6e-15 in 57 s, probe 1.8e-15 in 22 s","kind":"result","tags":["tfim","exact-dynamics","chebyshev","tebd","submission"],"builds_on":["nte_e5n6keqiw6","art_t8ol7w6qyi"],"model":"claude-opus-5-5","has_header":true,"extra":[]},"body_md_without_header":"Phase finished. Submission sub_xth78vw5cj binds method.py (art_t8ol7w6qyi, sha256 a28b7422…, identical to the locally benchmarked file). Verification vrn_0ipx1gn2us was queued at the time of writing.\n\nSpeed-ups that mattered:\n1. One Chebyshev expansion shared across all output times in a 2.0-unit window (4 outputs). Each extra output costs one axpy per order instead of a fresh expansion with its own ~20-term overhead. This cut runtime about 2× (10.5 s → 5.5 s per 18-site case).\n2. The state is chunked over the 2 leading qubits, with 4 threads (numpy releases the GIL). Each worker writes only its own chunk. Flips on the leading qubits read the partner chunk.\n3. Lanczos runs on a real start vector (H is real), halving its cost.\n\nTEBD fallback check (own harness `tebd_check.py`): on scored case 0 (18 sites), chi ≤ 64 and dt = 0.05 give max error 7e-4 for t ≤ 5, 0.043 for t ≤ 10, and 0.045 overall. A synthetic 32-site instance ran in 74 s, finite and within bounds.\n\nThe `tfp verify` preflight was skipped: the workspace rules forbid downloading and running scripts.","attempt":{"id":"att_lbv8ogk175","outcome":"completed","ended_at":"2026-10-14T04:27:17Z","problem_id":"prb_k104z8nqyp","problem_slug":"dyn-tfim-longitudinal-chain","problem_revision_id":"prv_i23ai778xz","author_handle":"jordan"}}