Finishes the Layer 1 analytical core. All six experiments run with honest, publication-quality figures; 71 tests green. - E3 region-matched grounding: `grounding.exercised` knob + per-region tail survival. Matched holds the exercised region's tail (0.49) where uniform spreads thin and lets it collapse (0.07). - E4 multi-teacher recombination: `run_coverage` runner. Union coverage matches U(K_T,rho,q) exactly. Finding: mean-mixture distillation shows NO surviving benefit (a conservation law — 1/K_T dilution cancels the union gain); a union-preserving max-merge (M2N2-style) does. E4 reports both operators. - E5 QD vs greedy: greedy drives fixation (H~0.01); QD holds H at 0.48-0.88, rising with the novelty exponent. - E6 re-mint gate: `arm` multi-override sweep. Re-minting a collapsed lineage locks in divergence of KL-to-original; gating on diversity prevents it. - E2 analysis add-ons (from the companion work order, numbers verified): new analysis.py (reduce_to_stationary, critical_grounding with bootstrap CI -> g*=0.048, 95% CI [0.047,0.050]); tail_band_metrics + per-band logging; the E2 figure rebuilt as a 2x2 (defined g*+CI, g=0 flagged as a finite-time artifact, tail item-vs-mass, per-rarity-band panel). Uses truth-mass-weighted tail coverage rather than the raw (martingale) tail_mass. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
253 lines
12 KiB
Markdown
253 lines
12 KiB
Markdown
# Work order: E2 analysis add-ons
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*Increment to the Lamarckian-Society Layer-1 build. Assumes the blueprint conventions
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(seeded RNG, config-driven, results in tidy DataFrames, figures are pure functions of
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`results.parquet`). All code below was written and tested against NumPy 2.x / pandas 3.x
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before hand-off; the "verified numbers" section gives the expected outputs so you can
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confirm your wiring reproduces them.*
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## Context
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E1 and E2 are validated: E1 reproduces the analytic geometric decay `H0(1-1/n)^t`
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(tail-first, support collapse, KL divergence); E2's stationary simulation points lie on
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the exact closed form `H_eq = H* * m(2n+m-1)/(n+2nm+m^2)`. Three refinements make the E2
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figure publication-honest. None change the dynamics; they are analysis + plotting only.
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1. **Operational `g*` with a bootstrap CI.** The middle E2 panel is a *smooth saturating*
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curve, not a sharp transition, so "critical g*" must be *defined*, not asserted:
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`g*` = the grounding fraction at which stationary `H` first reaches `frac`×`H*`
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(default `frac=0.95`). Report it with a percentile-bootstrap CI over replicates.
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2. **Tail-mass companion curve.** The right E2 panel plots fraction of tail *items* alive,
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which saturates low (~6%) because the deep Zipf tail is unrescuable at any feasible
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grounding. Add the frequency-weighted **tail-mass-retained** curve alongside it: mass
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is carried by the shallow tail and *is* rescued, so it looks healthy where item-count
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does not. Both are correct; showing both is the honest picture. (`tail_mass` is already
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a logged metric — this is a second series, no new storage.)
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3. **`g=0` point is a finite-time artifact.** In the middle panel it sits at `H≈0.10`,
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above the exact `H_eq(0)=0`, because at `g=0` there is no stationary state (still
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collapsing at the last generation). Either exclude `g=0` from the stationary fit or
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annotate that its true value is 0; don't let it read as a data–theory miss.
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**Optional but recommended (turns point 2 into a mechanism panel):** a per-rarity-band
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tail metric showing the deep band stays dead while the shallow band recovers — the
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`m·p*_i ≳ 1` threshold acting band-wise, and the direct motivation for E4/E6.
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---
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## 1. New module: `src/knowledge/analysis.py`
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Post-hoc analysis of E2 results. Pure NumPy/pandas, seeded, deterministic.
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```python
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import numpy as np
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import pandas as pd
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def reduce_to_stationary(df, value_col="heterozygosity", sweep_col="g",
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replicate_col="seed", gen_col="generation", last_frac=0.33):
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"""Per-generation frame -> one stationary value per (sweep, replicate), averaging
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`value_col` over the final `last_frac` of generations. Use for any logged metric
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(heterozygosity, tail_mass, ...)."""
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rows = []
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for (gval, rep), sub in df.groupby([sweep_col, replicate_col]):
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v = sub.sort_values(gen_col)[value_col].to_numpy()
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k = max(1, int(round(last_frac * v.size)))
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rows.append({sweep_col: gval, replicate_col: rep, value_col: v[-k:].mean()})
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return pd.DataFrame(rows)
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def _interp_crossing(g, H, target):
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"""First upward crossing of `target` by the (monotone-ish) curve H(g), by linear
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interpolation between grid points. Returns (g_star, status) with status in
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{'ok', 'below_grid', 'above_grid'}."""
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g = np.asarray(g, float); H = np.asarray(H, float)
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o = np.argsort(g); g, H = g[o], H[o]
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if H[0] >= target:
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return g[0], "below_grid" # already above at smallest g swept
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idx = np.where(H >= target)[0]
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if idx.size == 0:
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return g[-1], "above_grid" # never reaches target within swept range
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i = idx[0]
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g0, g1, H0, H1 = g[i - 1], g[i], H[i - 1], H[i]
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if H1 == H0:
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return g1, "ok"
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return g0 + (target - H0) * (g1 - g0) / (H1 - H0), "ok"
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def critical_grounding(stationary_df, H_star, frac=0.95, sweep_col="g",
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value_col="heterozygosity", n_boot=2000,
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ci=(2.5, 97.5), seed=0):
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"""Operational critical grounding fraction g*: the g at which stationary
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heterozygosity first reaches `frac` * `H_star`, with a percentile-bootstrap CI
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over replicates.
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`stationary_df`: one row per (sweep_col, replicate_col) with the stationary value
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(e.g. the output of reduce_to_stationary). `H_star`: heterozygosity of the truth,
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= metrics.heterozygosity(p_star). Returns a dict with g_star (point estimate on the
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replicate means), ci_low, ci_high, status, target_H, frac, n_boot.
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Note: 'status' flags right/left censoring. If the sweep does not bracket the target,
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widen the g grid rather than trusting a censored g*."""
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target = frac * H_star
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gs = np.sort(stationary_df[sweep_col].unique())
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by_g = {gv: stationary_df.loc[stationary_df[sweep_col] == gv, value_col].to_numpy()
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for gv in gs}
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mean_H = np.array([by_g[gv].mean() for gv in gs])
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g_star, status = _interp_crossing(gs, mean_H, target)
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rng = np.random.default_rng(seed)
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boots = np.empty(n_boot)
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for b in range(n_boot):
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Hb = np.array([rng.choice(by_g[gv], by_g[gv].size, replace=True).mean()
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for gv in gs])
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boots[b], _ = _interp_crossing(gs, Hb, target)
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lo, hi = np.percentile(boots, ci)
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return {"g_star": float(g_star), "ci_low": float(lo), "ci_high": float(hi),
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"status": status, "target_H": float(target), "frac": frac,
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"n_boot": n_boot}
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```
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---
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## 2. New online metric in `src/knowledge/metrics.py` (optional band panel)
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Compute this each generation from the current `p` and log the per-band arrays exactly
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like the existing per-region metrics (e.g. columns `tail_frac_alive_band{b}` and
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`tail_mass_alive_band{b}`, or long form). Both returned quantities are bounded in [0,1]
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— do **not** use a raw mass ratio (tiny deep-band denominators make it explode).
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```python
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def tail_band_metrics(p, p_star, tail_mask, n_bands=4, alive_eps=1e-9):
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"""Stratify the tail into `n_bands` equal-count rarity bands (band 0 = rarest /
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deepest). Return two BOUNDED [0,1] arrays of length n_bands:
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frac_alive[b] fraction of band-b items with p > alive_eps
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truth_mass_alive[b] share of band-b's TRUE mass (sum p_star) carried by
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still-alive items
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Averaged over replicates, deeper bands sit strictly below shallower ones and the
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gap narrows as grounding rises -- the per-item m*p*_i >~ 1 survival threshold made
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visible (blueprint prediction 4). Single-run values are noisy; always average over
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replicates before plotting."""
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import numpy as np
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idx = np.where(tail_mask)[0]
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order = idx[np.argsort(p_star[idx])] # rarest first
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bands = np.array_split(order, n_bands)
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frac_alive = np.empty(n_bands)
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truth_mass_alive = np.empty(n_bands)
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for b, items in enumerate(bands):
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alive = p[items] > alive_eps
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frac_alive[b] = alive.mean()
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ps = p_star[items]
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truth_mass_alive[b] = ps[alive].sum() / ps.sum() if ps.sum() > 0 else np.nan
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return frac_alive, truth_mass_alive
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```
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---
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## 3. Figure updates: `figures/plot_E2.py`
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- **Middle panel:** call `critical_grounding(reduce_to_stationary(df), H_star, frac=0.95)`
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and draw a vertical line/marker at `g_star` with a shaded CI band; annotate
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`g* ≈ {g_star:.3f} (95% CI [...])`. Also report `frac=0.90` in the caption so the
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"3–5%" range is explicit. Soften the title from "critical grounding ratio" to
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e.g. "grounding saturates by g* ≈ 0.05 (95% of H*)".
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- **Right panel:** add stationary **tail-mass-retained** vs g as a second series
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(`reduce_to_stationary(df, value_col="tail_mass")`), on a twin axis if scales differ,
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so mass-healthy vs items-poor is visible in one panel.
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- **`g=0`:** drop it from the stationary fit *or* mark it hollow with a note
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"pre-convergence; true H_eq(0)=0".
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- **Optional band panel:** if `tail_band_metrics` is logged, add a small-multiples or
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grouped-bar panel of `frac_alive` per band across the g sweep (replicate-averaged).
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---
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## 4. Tests to add (`tests/test_analysis.py`)
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```python
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import numpy as np, pandas as pd, pytest
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from knowledge.analysis import reduce_to_stationary, critical_grounding
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from knowledge.metrics import tail_band_metrics
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def _H_eq(n, m, Hs): return Hs * m * (2 * n + m - 1) / (n + 2 * n * m + m * m)
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def _synthetic_E2(n=200, Hs=0.95, reps=100, seed=1):
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gs = [0.0, 0.005, 0.01, 0.02, 0.05, 0.1, 0.2, 0.4]
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rng = np.random.default_rng(seed); rows = []
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for g in gs:
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m = 0 if g == 0 else int(round(g * n / (1 - g)))
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Htrue = 0.10 if g == 0 else _H_eq(n, m, Hs) # g=0: finite-time artifact
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for s in range(reps):
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rows.append({"g": g, "seed": s, "heterozygosity": Htrue + rng.normal(0, 0.004)})
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return pd.DataFrame(rows)
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def test_critical_grounding_matches_known_crossing():
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stat = _synthetic_E2()
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r = critical_grounding(stat, H_star=0.95, frac=0.95, seed=7)
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assert r["status"] == "ok"
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assert 0.03 < r["g_star"] < 0.07 # ~0.047 for frac=0.95
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assert r["ci_low"] <= r["g_star"] <= r["ci_high"]
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r90 = critical_grounding(stat, H_star=0.95, frac=0.90, seed=7)
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assert r90["g_star"] < r["g_star"] # lower bar -> smaller g*
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def test_reduce_to_stationary_recovers_plateau():
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# constant plateau + noise -> mean ~ plateau
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rng = np.random.default_rng(0); rows = []
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for g, plateau in [(0.02, 0.843), (0.05, 0.908)]:
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for s in range(20):
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for t in range(300):
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v = (0.95 if t < 50 else plateau) + rng.normal(0, 0.003)
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rows.append({"g": g, "seed": s, "generation": t, "heterozygosity": v})
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red = reduce_to_stationary(pd.DataFrame(rows), last_frac=0.33)
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means = red.groupby("g")["heterozygosity"].mean()
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assert means[0.02] == pytest.approx(0.843, abs=0.01)
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assert means[0.05] == pytest.approx(0.908, abs=0.01)
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def test_tail_band_deep_below_shallow():
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# grounded dynamics on a Zipf tail: deepest band <= shallowest band, replicate-avg
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K = 1000; s = 1.1
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w = 1.0 / np.arange(1, K + 1) ** s; p_star = w / w.sum()
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tail_mask = p_star < 1e-3
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n, m = 200, 10
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FA = np.zeros(4)
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for r in range(20):
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rng = np.random.default_rng(1000 + r); p = p_star.copy()
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for _ in range(600):
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c = rng.multinomial(n, p) + rng.multinomial(m, p_star); p = c / c.sum()
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fa, _ = tail_band_metrics(p, p_star, tail_mask, n_bands=4)
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FA += fa
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FA /= 20
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assert FA[0] <= FA[-1] # deepest no better than shallowest
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assert FA[-1] > FA[0] # and strictly worse on average
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```
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---
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## Verified numbers (expected outputs — confirm your wiring reproduces these)
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On the synthetic E2 set (n=200, H*=0.95, exact H_eq + N(0,0.004) noise, 100 reps):
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| frac | g* (point) | 95% CI (tight, low-noise synthetic) |
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|------|-----------|--------------------------------------|
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| 0.90 | ~0.026 | ~[0.025, 0.026] |
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| 0.95 | ~0.047 | ~[0.047, 0.048] |
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| 0.99 | ~0.25 | ~[0.22, 0.27] |
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(Real E2 replicate spread will widen these CIs — that is expected and correct.)
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`reduce_to_stationary` on a plateau frame recovers 0.843 (g=0.02) and 0.908 (g=0.05).
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`tail_band_metrics`, grounded Zipf tail (K=1000, tail=p*<1e-3, 889 tail items), 40 reps,
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`frac_alive` per band [0=deepest .. 3=shallowest]:
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| g | band0 | band1 | band2 | band3 |
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|------|-------|-------|-------|-------|
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| 0.0 | 0.000 | 0.000 | 0.000 | 0.000 |
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| 0.01 | 0.002 | 0.002 | 0.004 | 0.010 |
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| 0.05 | 0.004 | 0.009 | 0.012 | 0.033 |
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| 0.20 | 0.015 | 0.022 | 0.032 | 0.075 |
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Monotone (deeper = worse) at every g>0; all bands rise with g; deep band lags throughout.
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