Fix: _local_order divided by fp*fp that underflows to 0 for a tiny nonzero slope (ZeroDivisionError, caught by the sweep harness and charged as a failure - this is what had moved Table 6's order cells after the sign fix). Pinned by a test that fails on the old code. Every sweep file regenerated on the server (run_all_sweeps.sh). verify_article: skip result files that are not grid lists (it crashed on the out-of-sample dicts). Verifier now completes: 224 OK, 57 stale numbers in the paper to update (Table 6 again 7 of 7).

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
2026-09-21 20:34:19 +01:00
parent 80610e5c27
commit 2c458c51dc
16 changed files with 153 additions and 78 deletions
@@ -682,7 +682,13 @@ def _local_order(x2, f2, x1, f1, x0, f0):
    fpp = 2.0 * d012                   # f''(x2) on the parabola
    if fp == 0.0 or not math.isfinite(fp) or not math.isfinite(fpp):
        return 1.0
-    theta = f2 * fpp / (fp * fp)
+    den = fp * fp
+    if den == 0.0:
+        # fp nonzero but its square underflows (found 2026-09-21: a ZeroDivisionError that
+        # the sweep harness caught and charged as a failure, which is what moved Table 6's
+        # order cells after the sign fix); no order can be read - decline, as for fp == 0
+        return 1.0
+    theta = f2 * fpp / den
    if not math.isfinite(theta) or not (0.0 < theta < 1.0):
        return 1.0
    m = 1.0 / (1.0 - theta)