Files
sim-numerics/tests/test_flat_gate.py
T
vvsandClaude Opus 5 1842eb0765 Flat regime: exit by midpoint similarity (flatstickexit), one judgment at entry and exit (flatjudge), entry by analogy (flatanalog).
PREREG_flat_exit: NOT accepted - APS 2806 -> 3125, CHA 3220 -> 2503 (the exit is earned: APS 6897 without it).
PREREG_flat_judge: NOT accepted (smoke) - APS 3009, CHA 2486: at the model's point f is small by construction, the judgment cannot tell flat from simple there.
PREREG_flat_analogy: ACCEPTED with G2. Entry = unkept promise AND the (xi, phi) configuration nearer to its own past than to the line AND the pair's similarity exponent m >= 2. Projection + G2: APS 2782 -> 2780 (below Chandrupatla 2787, per problem 95/20/38 p=8e-7), CHA 3169 -> 2625, guarantee holds. Without G2: APS 2806 -> 2807 (fails by one call), CHA 2635. Simple roots are spared exactly (cost unchanged); flat families 1823 -> 1238, entry comes late. Goal (below Chandrupatla on both) NOT met: CHA 2625 vs 2441, per problem 9/6/25.
Server regression x2: 1052 passed, 1 failed = the expected paper-number check.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
2026-09-21 14:55:45 +01:00

270 lines
12 KiB
Python

"""Pins for PREREG_flat_regime_2026-09-21.md: the flat gate (prestep='flat')."""
from __future__ import annotations
import math
import pytest
from simroot.pure import pure_root
XTOL, MAXFEV = 1e-12, 200
PROBS = (
(lambda t: t ** 3 - 2.0 * t - 5.0, 1.0, 4.0),
(lambda t: math.exp(t) - 2.0, 0.0, 3.0),
(lambda t: 6.0 * (t - 2.0) ** 5, 0.0, 10.0),
(lambda t: t ** 19, -10.0, 100.0),
)
@pytest.mark.parametrize("f,a,b", PROBS)
@pytest.mark.parametrize("guard", ("project", "credit", "safe"))
def test_the_default_is_untouched(f, a, b, guard):
ref = pure_root(f, a, b, XTOL, MAXFEV, similarity="ratio", scale="derived3", guard=guard)
off = pure_root(f, a, b, XTOL, MAXFEV, similarity="ratio", scale="derived3", guard=guard,
prestep="none")
assert ref == off
@pytest.mark.parametrize("f,a,b", PROBS)
@pytest.mark.parametrize("guard", ("project", "credit"))
@pytest.mark.parametrize("ext", ("none", "pattern"))
def test_the_guarantee_holds_with_the_gate(f, a, b, guard, ext):
x, n, ok = pure_root(f, a, b, XTOL, MAXFEV, similarity="ratio", scale="derived3",
guard=guard, prestep="flat", extrapolate=ext)
assert ok and min(a, b) <= x <= max(a, b)
half = math.ceil(math.log2(abs(b - a) / XTOL))
assert n <= (2 * half + 3 if guard == "project" else half + 4), n
@pytest.mark.parametrize("f,a,b", PROBS)
@pytest.mark.parametrize("guard", ("project", "credit"))
@pytest.mark.parametrize("ext", ("none", "pattern"))
def test_the_guarantee_holds_with_the_twice_gate(f, a, b, guard, ext):
x, n, ok = pure_root(f, a, b, XTOL, MAXFEV, similarity="ratio", scale="derived3",
guard=guard, prestep="flat2", extrapolate=ext)
assert ok and min(a, b) <= x <= max(a, b)
half = math.ceil(math.log2(abs(b - a) / XTOL))
assert n <= (2 * half + 3 if guard == "project" else half + 4), n
def test_the_twice_gate_is_silent_where_the_model_is_exact_and_fires_on_a_power():
st = {}
pure_root(lambda t: 3.0 * t - 1.0, -2.0, 5.0, XTOL, MAXFEV, similarity="ratio",
scale="derived3", guard="project", prestep="flat2", stats=st)
assert st["pre_refused"] == 0
st = {}
pure_root(lambda t: t ** 9, -1.0, 2.0, XTOL, MAXFEV, similarity="ratio",
scale="derived3", guard="project", prestep="flat2", stats=st)
assert st["pre_refused"] > 0
@pytest.mark.parametrize("f,a,b", PROBS)
@pytest.mark.parametrize("guard", ("project", "credit"))
@pytest.mark.parametrize("ext", ("none", "pattern"))
def test_the_guarantee_holds_with_the_creep_gate(f, a, b, guard, ext):
x, n, ok = pure_root(f, a, b, XTOL, MAXFEV, similarity="ratio", scale="derived3",
guard=guard, prestep="flatcreep", extrapolate=ext)
assert ok and min(a, b) <= x <= max(a, b)
half = math.ceil(math.log2(abs(b - a) / XTOL))
assert n <= (2 * half + 3 if guard == "project" else half + 4), n
def test_the_creep_gate_is_silent_on_a_line_fires_on_a_power_and_spares_a_simple_root():
"""Measured before pinning: silent where the model is exact, fires on x^9, and does
NOT fire on x^3 - 2x - 5 over [1, 4], where the single flag fired once."""
runs = {}
for name, f, a, b in (("line", lambda t: 3.0 * t - 1.0, -2.0, 5.0),
("x9", lambda t: t ** 9, -1.0, 2.0),
("cubic", lambda t: t ** 3 - 2.0 * t - 5.0, 1.0, 4.0)):
st = {}
pure_root(f, a, b, XTOL, MAXFEV, similarity="ratio", scale="derived3",
guard="project", prestep="flatcreep", stats=st)
runs[name] = st["pre_refused"]
assert runs["line"] == 0 and runs["x9"] > 0 and runs["cubic"] == 0, runs
def test_the_gate_never_fires_where_the_model_is_exact():
"""On a straight line the model's step lands on the root: r = 0, never >= 1/4."""
st = {}
pure_root(lambda t: 3.0 * t - 1.0, -2.0, 5.0, XTOL, MAXFEV, similarity="ratio",
scale="derived3", guard="project", prestep="flat", stats=st)
assert st["pre_refused"] == 0
def test_the_gate_fires_on_a_pure_power():
"""On x^9 the tangent step leaves (8/9)^9 = 0.35 of |f| on the same side."""
st = {}
pure_root(lambda t: t ** 9, -1.0, 2.0, XTOL, MAXFEV, similarity="ratio",
scale="derived3", guard="project", prestep="flat", stats=st)
assert st["pre_refused"] > 0
# ---- PREREG_flat_stick_2026-09-21: the sticky flat regime and its midpoint ablation ----
from simroot.pure import _order_from_promise, _order_split # noqa: E402
@pytest.mark.parametrize("m", (2.0, 3.0, 5.0, 9.0, 19.0, 100.0))
def test_the_order_is_read_back_from_its_own_promise(m):
r = (1.0 - 1.0 / m) ** m
assert _order_from_promise(r) == pytest.approx(m, rel=1e-9)
def test_no_finite_order_at_or_above_one_over_e_gives_the_midpoint():
assert math.isinf(_order_from_promise(math.exp(-1.0)))
assert math.isinf(_order_from_promise(0.9))
assert _order_split(-1.0, -3.0, 2.0, 5.0, math.inf) == 0.5
@pytest.mark.parametrize("m", (1, 3, 5, 9))
def test_the_split_lands_on_the_root_of_an_exact_power(m):
f = lambda t: (t - 0.3) ** m # noqa: E731
assert _order_split(-1.0, f(-1.0), 2.0, f(2.0), float(m)) == pytest.approx(0.3, abs=1e-12)
def test_the_split_does_not_overflow_on_extreme_ends():
x = _order_split(0.0, -1e-300, 1.0, 1e300, 2.0)
assert 0.0 <= x < 1e-100
x = _order_split(0.0, -1e300, 1.0, 1e-300, 2.0)
assert 1.0 - x < 1e-100 and x <= 1.0
@pytest.mark.parametrize("f,a,b", PROBS)
@pytest.mark.parametrize("guard", ("project", "credit"))
@pytest.mark.parametrize("ext", ("none", "pattern"))
@pytest.mark.parametrize("gate", ("flatstick", "flatstickmid"))
def test_the_guarantee_holds_with_the_sticky_regime(f, a, b, guard, ext, gate):
x, n, ok = pure_root(f, a, b, XTOL, MAXFEV, similarity="ratio", scale="derived3",
guard=guard, prestep=gate, extrapolate=ext)
assert ok and min(a, b) <= x <= max(a, b)
half = math.ceil(math.log2(abs(b - a) / XTOL))
assert n <= (2 * half + 3 if guard == "project" else half + 4), n
@pytest.mark.parametrize("gate", ("flatstick", "flatstickmid"))
def test_the_sticky_regime_is_silent_on_a_line_and_holds_on_a_power(gate):
st = {}
pure_root(lambda t: 3.0 * t - 1.0, -2.0, 5.0, XTOL, MAXFEV, similarity="ratio",
scale="derived3", guard="project", prestep=gate, stats=st)
assert st["pre_refused"] == 0
st = {}
_x, n, _ok = pure_root(lambda t: t ** 9, -1.0, 2.0, XTOL, MAXFEV, similarity="ratio",
scale="derived3", guard="project", prestep=gate, stats=st)
# once entered, every later non-forced step is a split: many, not one
assert st["pre_refused"] >= 3, st
def test_an_infinite_end_gives_the_midpoint_not_nan():
"""Audit bug 2026-09-21: an infinite |f| made lq nan, and the nan step reached the
safeguard before the loop checked finiteness."""
assert _order_split(0.0, -math.inf, 2.0, 1.0, 3.0) == 1.0
assert _order_split(0.0, -math.inf, 2.0, math.inf, 3.0) == 1.0
# ---- PREREG_flat_exit_2026-09-21: leaving the sticky regime by similarity at the midpoint ----
@pytest.mark.parametrize("f,a,b", PROBS)
@pytest.mark.parametrize("guard", ("project", "credit"))
@pytest.mark.parametrize("ext", ("none", "pattern"))
def test_the_guarantee_holds_with_the_exit(f, a, b, guard, ext):
x, n, ok = pure_root(f, a, b, XTOL, MAXFEV, similarity="ratio", scale="derived3",
guard=guard, prestep="flatstickexit", extrapolate=ext)
assert ok and min(a, b) <= x <= max(a, b)
half = math.ceil(math.log2(abs(b - a) / XTOL))
assert n <= (2 * half + 3 if guard == "project" else half + 4), n
def _exit_stats(f, a, b):
st = {}
pure_root(f, a, b, XTOL, MAXFEV, similarity="ratio", scale="derived3", guard="project",
prestep="flatstickexit", stats=st)
return st.get("stick_entries", 0), st.get("stick_exits", 0)
def test_the_exit_leaves_a_false_entry_and_keeps_a_true_one():
"""Measured before pinning: a simple root that trips the flag (the cubic, exp) leaves
the regime at a midpoint; pure powers, scale-invariant, never do."""
assert _exit_stats(lambda t: 3.0 * t - 1.0, -2.0, 5.0) == (0, 0)
assert _exit_stats(lambda t: t ** 3 - 2.0 * t - 5.0, 1.0, 4.0) == (1, 1)
assert _exit_stats(lambda t: math.exp(t) - 2.0, 0.0, 3.0) == (1, 1)
for f, a, b in ((lambda t: t ** 9, -1.0, 2.0), (lambda t: t ** 19, -10.0, 100.0),
(lambda t: 6.0 * (t - 2.0) ** 5, 0.0, 10.0)):
ent, ex = _exit_stats(f, a, b)
assert ent >= 1 and ex == 0, (ent, ex)
def test_the_exit_does_not_touch_the_other_sticky_modes():
for gate in ("flatstick", "flatstickmid"):
st = {}
pure_root(lambda t: math.exp(t) - 2.0, 0.0, 3.0, XTOL, MAXFEV, similarity="ratio",
scale="derived3", guard="project", prestep=gate, stats=st)
assert st.get("stick_exits", 0) == 0
# ---- PREREG_flat_judge_2026-09-21: one similarity judgment at entry and exit ----
@pytest.mark.parametrize("f,a,b", PROBS)
@pytest.mark.parametrize("guard", ("project", "credit"))
@pytest.mark.parametrize("ext", ("none", "pattern"))
def test_the_guarantee_holds_with_the_judge(f, a, b, guard, ext):
x, n, ok = pure_root(f, a, b, XTOL, MAXFEV, similarity="ratio", scale="derived3",
guard=guard, prestep="flatjudge", extrapolate=ext)
assert ok and min(a, b) <= x <= max(a, b)
half = math.ceil(math.log2(abs(b - a) / XTOL))
assert n <= (2 * half + 3 if guard == "project" else half + 4), n
def test_the_judge_is_silent_on_a_line_and_holds_a_pure_power():
st = {}
pure_root(lambda t: 3.0 * t - 1.0, -2.0, 5.0, XTOL, MAXFEV, similarity="ratio",
scale="derived3", guard="project", prestep="flatjudge", stats=st)
assert st.get("stick_entries", 0) == 0 and st["pre_refused"] == 0
st = {}
pure_root(lambda t: t ** 19, -10.0, 100.0, XTOL, MAXFEV, similarity="ratio",
scale="derived3", guard="project", prestep="flatjudge", stats=st)
assert st.get("stick_entries", 0) >= 1 and st.get("stick_exits", 0) == 0, st
# ---- PREREG_flat_analogy_2026-09-21: entry by analogy with the run's own past ----
from simroot.pure import _analogous_and_steep, _config3 # noqa: E402
@pytest.mark.parametrize("f,a,b", PROBS)
@pytest.mark.parametrize("guard", ("project", "credit"))
@pytest.mark.parametrize("ext", ("none", "pattern"))
def test_the_guarantee_holds_with_the_analogy_entry(f, a, b, guard, ext):
x, n, ok = pure_root(f, a, b, XTOL, MAXFEV, similarity="ratio", scale="derived3",
guard=guard, prestep="flatanalog", extrapolate=ext)
assert ok and min(a, b) <= x <= max(a, b)
half = math.ceil(math.log2(abs(b - a) / XTOL))
assert n <= (2 * half + 3 if guard == "project" else half + 4), n
def test_the_analogy_entry_spares_simple_roots_and_catches_powers():
"""Measured before pinning: the cubic and exp, which trip the single flag, never
enter, and cost exactly what the rule costs without the regime."""
for f, a, b in ((lambda t: 3.0 * t - 1.0, -2.0, 5.0),
(lambda t: t ** 3 - 2.0 * t - 5.0, 1.0, 4.0),
(lambda t: math.exp(t) - 2.0, 0.0, 3.0)):
st = {}
_x, n1, _ = pure_root(f, a, b, XTOL, MAXFEV, similarity="ratio", scale="derived3",
guard="project", prestep="flatanalog", stats=st)
_x, n0, _ = pure_root(f, a, b, XTOL, MAXFEV, similarity="ratio", scale="derived3",
guard="project")
assert st.get("stick_entries", 0) == 0 and n1 == n0
for f, a, b in ((lambda t: t ** 9, -1.0, 2.0), (lambda t: t ** 19, -10.0, 100.0),
(lambda t: 6.0 * (t - 2.0) ** 5, 0.0, 10.0)):
st = {}
pure_root(f, a, b, XTOL, MAXFEV, similarity="ratio", scale="derived3",
guard="project", prestep="flatanalog", stats=st)
assert st.get("stick_entries", 0) >= 1
def test_a_line_is_never_analogous_and_an_exact_power_repeats_with_its_order():
line = [_config3(x, 3 * x, xp, 3 * xp, xp2, 3 * xp2)
for x, xp, xp2 in ((0.1, 0.5, 1.0), (0.05, 0.1, 0.5))]
assert line[0][0] == pytest.approx(line[0][1]) # phi = xi on a line
assert not _analogous_and_steep(line[1], [line[0]])
p = lambda t: t ** 5 # noqa: E731
old = _config3(0.4, p(0.4), 0.8, p(0.8), 1.6, p(1.6))
new = _config3(0.1, p(0.1), 0.2, p(0.2), 0.4, p(0.4)) # the same shape, zoomed by 4
assert new[0] == pytest.approx(old[0]) and new[1] == pytest.approx(old[1])
assert _analogous_and_steep(new, [old])