Marcin Pawlowski ac6a309e58
Review fixes + high-precision design-band delay study
Acts on a correctness/completeness review of the countable uncle model
and its report material.

Correctness fixes in the report:
- s3.4 quoted 0.998 for W_abs=10 at the 8s budget; the run says 0.9963.
- s1 claimed both models >= 0.996 at U >= 1; countable U=2 delta=8 is
  0.9955. Corrected to >= 0.995.
- The s3.2 table presented two cells (U=1 at delta 16 and 32) as model
  differences. They are not resolvable: t = 0.46 and 0.47 over 5
  replicates. The table now carries +-SEM and a t per cell.
- s3.4 claimed the ~7-block-interval floor "carries over unchanged".
  Accuracy is still climbing past W=7 at every delay (8s: 0.989 ->
  0.996), so the claim is dropped. The 32s curve is non-monotonic with
  replicate SD up to 0.22 and is now flagged as noise, not a trend.
- 1-r was attributed to the first-fork restriction alone; it is the
  combined first-fork and capacity loss, which this measurement cannot
  separate. Hedged to match fig32's own axis label.

Completeness: the U=0 negative control was swept but never reported.
With no uncles the two models are identical by construction, yet they
differ by -0.23 at delta_max=32 (t=2.1) because they draw independent
RNG streams. That is the noise floor the rest of the grid must clear,
and it is now in s3.2, s9, fig30 and the config header.

New study (configs/fine-delay.yaml, scripts/plot_fine_delay.py, s3.2a,
fig34/fig35): the design band delta_max 1-5 at 40 replicates, both
models. Findings: every U >= 1 cell of both models lands in
0.998-1.001, flat in delay, while U=0 decays 0.810 -> 0.640. No
individual cell resolves a model difference (widest 95% CI +-0.15pp;
max t=2.59 vs Bonferroni 2.94 over 15 cells). Pooled across uncle caps
the first-fork cost is monotone in delay and separates from zero only
at delta_max=5 (-0.0014 +- 0.0007, t=3.7) -- below 0.15% everywhere in
the band, against +-0.9% per-epoch sampling noise.

Code:
- deep_ref_share is identically 0 on every real countable run: for a
  chain block B the producer's chain below B is the counting chain
  below B, so the counting-side parent-on-chain re-check cannot reject
  what selection emitted. It is a drift alarm, not a rate. Documented
  as such in measure.py, the plot docstring and the config header, and
  pinned by a new end-to-end test.
- Removed annotate_uncles: a second countable implementation that
  production never called, while carrying most of the selection test
  coverage. Tests now drive select_uncles_at_production through an
  annotate_via_production replay helper -- same assertions, live path.
- Added tests for the two previously uncovered branches of the live
  selection: the pmin/below chain walk that resolves parent-on-chain
  for candidates whose parent sits below the window, and the
  occupied-slot exclusion built from the chain walk.
- theory.q_effective and theory.window_miss_prob were unused and
  untested. Now used (the prediction figure reconstructs q_u through
  the identity the report quotes) and tested. The window_miss_prob test
  records that its "~ e^-W" docstring is the f->0 limit: the true decay
  is e^-1.017W at f=1/30, 16% off by W=10.
- Shared sem()/recovery_rate() moved into figures_pernode.py; fig30 and
  fig33 regenerated with SEM error bars and the U=0 control curve.
- Fixed the pre-existing E501 in bootstrap_dynamics.py; ruff clean.

Report prose reworked to read standalone: the countable model is
described as the rules under analysis and the former model as a
labelled "unrestricted" comparison baseline, with no dated banners and
no round-to-round narration.

Tests: 209 passed (was 202).

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
2026-08-04 20:48:38 +02:00

84 lines
3.3 KiB
Python

import numpy as np
from tsi_sim import theory
F = 1 / 30
T = 10000
def test_expected_ratio_unbiased_at_q1():
assert abs(float(theory.expected_ratio(F, 1.0)) - 1.0) < 1e-12
def test_expected_ratio_monotone_in_q():
qs = np.linspace(0.5, 1.0, 20)
er = theory.expected_ratio(F, qs)
assert np.all(np.diff(er) > 0) # accuracy improves as q -> 1
assert np.all(er <= 1.0 + 1e-12) # always an underestimate
def test_variance_bound_matches_at_q1():
v = float(theory.variance_ratio(F, 1.0, T))
assert abs(v - theory.variance_bound(F, T)) < 1e-15
def test_optimal_beta_is_half_stability_bound():
for q in (0.7, 0.85, 0.95):
opt = float(theory.optimal_beta(F, q))
bound = float(theory.beta_stability_bound(F, q))
assert abs(opt - bound / 2) < 1e-12
def test_block_count_ceiling_above_one():
c = theory.block_count_ceiling(F)
assert 1.015 < c < 1.02 # -ln(1-1/30)/(1/30) ~ 1.01705
def test_fixed_point_bias_about_one_percent():
b = theory.fixed_point_bias(F)
assert abs(b - (F / (33 / 1000))) < 1e-12
assert 1.005 < b < 1.02
def test_q_effective_interpolates_between_q_and_one():
# r = 0 -> no recovery (chain-only q); r = 1 -> every wasted slot recovered (q_u = 1).
for q in (0.3, 0.65, 0.9):
assert abs(float(theory.q_effective(q, 0.0)) - q) < 1e-15
assert abs(float(theory.q_effective(q, 1.0)) - 1.0) < 1e-15
# monotone and strictly between for partial recovery
half = float(theory.q_effective(q, 0.5))
assert q < half < 1.0
def test_q_effective_round_trips_the_measured_recovery_rate():
# The identity the report quotes: given measured q and q_u, r = (q_u - q)/(1 - q)
# reconstructs q_u exactly. This is how plot_countable_vs_old.py derives its overlay.
for q, q_u in ((0.3129, 0.6147), (0.5380, 0.9874), (0.7485, 0.9992)):
r = (q_u - q) / (1.0 - q)
assert abs(float(theory.q_effective(q, r)) - q_u) < 1e-12
def test_q_effective_recovers_unbiased_equilibrium():
# Full recovery must lift the equilibrium to exactly 1 for any starting q.
for q in (0.3, 0.65, 0.9):
assert abs(float(theory.expected_ratio(F, theory.q_effective(q, 1.0))) - 1.0) < 1e-12
def test_window_miss_prob_decays_as_exp_minus_w():
# P(no canonical block in w_u = W/f slots) = (1-f)^(W/f) = exp(W * ln(1-f)/f).
# The docstring's "~ e^-W" is the f -> 0 limit: ln(1-f)/f = -(1 + f/2 + ...) = -1.0170
# at f = 1/30, so the true decay is slightly FASTER than e^-W, by a factor that grows
# with W (16% low by W = 10). Assert the exact form, and bracket the heuristic.
rate = np.log(1.0 - F) / F
assert -1.02 < rate < -1.0
for w_abs in (1.0, 3.0, 10.0):
p = float(theory.window_miss_prob(F, w_abs))
assert abs(p - (1.0 - F) ** (w_abs / F)) < 1e-15
assert abs(p - np.exp(rate * w_abs)) < 1e-15 # exact closed form
assert np.exp(-1.02 * w_abs) < p < np.exp(-w_abs) # brackets the e^-W heuristic
# the spec default W = 10 makes the window a negligible loss channel
assert float(theory.window_miss_prob(F, 10.0)) < 1e-4
# strictly decreasing in W
ps = [float(theory.window_miss_prob(F, w)) for w in (1, 2, 3, 5, 7, 10)]
assert all(a > b for a, b in zip(ps[:-1], ps[1:], strict=True))