Resolving Landmark Bottleneck / stage2_bench.py

✓✓ Beats tuned baseline

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  1import json, math, random, time, sys
  2from pathlib import Path
  3import numpy as np
  4import torch
  5from torch import nn
  6
  7sys.path.insert(0, '/home/maxwelhelp/all/math2nn')
  8from bench import train_model, evaluate, sweep_baseline, make_report
  9from graph_landmark_track import get_dataset
 10
 11SEEDS = tuple(range(8))
 12SWEEP_SEEDS = (0, 1, 2, 3)
 13LRS = [1e-3, 3e-3, 1e-2]
 14EPOCHS = 22
 15NTR, NTE = 400, 200
 16S = 8
 17
 18
 19def seed_all(seed):
 20    random.seed(seed); np.random.seed(seed); torch.manual_seed(seed)
 21    if torch.cuda.is_available():
 22        try: torch.cuda.manual_seed_all(seed)
 23        except Exception: pass
 24
 25
 26def greedy_landmarks(A, budget):
 27    """Greedily split currently colliding node signature groups."""
 28    n = A.shape[0]
 29    incoming = A.T.astype(np.uint8)  # node x candidate, candidate -> node
 30    chosen, remaining = [], list(range(n))
 31    Z = np.zeros((n, 0), dtype=np.uint8)
 32    for _ in range(min(budget, n)):
 33        _, inv = np.unique(Z, axis=0, return_inverse=True)
 34        groups = [np.flatnonzero(inv == g) for g in range(int(inv.max()) + 1)] if Z.shape[1] else [np.arange(n)]
 35        if all(len(g) <= 1 for g in groups): break
 36        best_q, best_score = None, -1
 37        for q in remaining:
 38            bit = incoming[:, q]
 39            score = 0
 40            for inds in groups:
 41                if len(inds) > 1:
 42                    k = int(bit[inds].sum()); score += k * (len(inds)-k)
 43            if score > best_score:
 44                best_q, best_score = q, score
 45        if best_q is None or best_score <= 0: break
 46        chosen.append(best_q); remaining.remove(best_q)
 47        Z = np.column_stack((Z, incoming[:, best_q]))
 48    return chosen
 49
 50
 51def signatures(A, landmarks):
 52    return A[np.asarray(landmarks), :].T.astype(np.float32)
 53
 54
 55def collision_count(Z):
 56    return int(Z.shape[0] - np.unique(Z, axis=0).shape[0])
 57
 58
 59class SharedGraphTransformer(nn.Module):
 60    def __init__(self, n_nodes, channels=9, d=32):
 61        super().__init__()
 62        self.inp = nn.Linear(channels, d)
 63        self.pos = nn.Parameter(torch.zeros(1, n_nodes, d))
 64        nn.init.normal_(self.pos, std=.02)
 65        layer = nn.TransformerEncoderLayer(d, nhead=2, dim_feedforward=64,
 66                                           batch_first=True, dropout=0.0)
 67        self.enc = nn.TransformerEncoder(layer, 2)
 68        self.head = nn.Linear(d, 1)
 69
 70    def forward(self, x):
 71        h = self.inp(x) + self.pos[:, :x.shape[1]]
 72        return self.head(self.enc(h))
 73
 74
 75def prepared(seed, idea):
 76    ds = get_dataset(seed, NTR, NTE)
 77    A = ds['adjacency']
 78    L = greedy_landmarks(A, S)
 79    Z = signatures(A, L)
 80    # Fixed width: baseline has the same channels, but no graph information.
 81    ztr = np.broadcast_to(Z[None, :, :], (NTR, Z.shape[0], Z.shape[1])).copy() if idea else np.zeros((NTR, Z.shape[0], S), np.float32)
 82    zte = np.broadcast_to(Z[None, :, :], (NTE, Z.shape[0], Z.shape[1])).copy() if idea else np.zeros((NTE, Z.shape[0], S), np.float32)
 83    ds['xtr'] = torch.from_numpy(np.concatenate([ds['xtr'], ztr], axis=2)).float()
 84    ds['xte'] = torch.from_numpy(np.concatenate([ds['xte'], zte], axis=2)).float()
 85    ds['ytr'] = torch.from_numpy(ds['ytr']).float(); ds['yte'] = torch.from_numpy(ds['yte']).float()
 86    ds['input_shape'] = tuple(ds['xtr'].shape[1:])
 87    return ds, L, Z
 88
 89
 90def run(kind, lr, seed, return_info=False):
 91    seed_all(seed)
 92    ds, L, Z = prepared(seed, kind == 'idea')
 93    model = SharedGraphTransformer(ds['xtr'].shape[1], ds['xtr'].shape[2])
 94    net, metric, hist = train_model(model, ds, epochs=EPOCHS, lr=lr,
 95                                    batch=128, weight_decay=0.0, log=lambda *a, **k: None)
 96    if metric is None: raise RuntimeError('training failed')
 97    if return_info:
 98        net = net.cpu()
 99        with torch.no_grad():
100            pred = net(ds['xte']).detach().cpu().numpy()
101        return float(metric), {'landmarks': L, 'collisions': collision_count(Z) if kind == 'idea' else Z.shape[0]-1,
102            'collision_rate': (collision_count(Z) if kind == 'idea' else Z.shape[0]-1)/Z.shape[0],
103            'prediction_std': float(pred.std()), 'target_std': float(ds['yte'].numpy().std()),
104            'pred_target_corr': float(np.corrcoef(pred.reshape(-1), ds['yte'].numpy().reshape(-1))[0,1])}
105    return float(metric)
106
107
108def factory(kind, cfg):
109    return lambda seed: run(kind, float(cfg['lr']), seed)
110
111
112def mechanism_signature():
113    vals = []
114    for seed in SEEDS:
115        b, bi = run('baseline', 3e-3, seed, True)
116        i, ii = run('idea', 3e-3, seed, True)
117        vals.append({'seed': seed, 'baseline_metric': b, 'idea_metric': i,
118                     'baseline_collisions': bi['collisions'], 'idea_collisions': ii['collisions'],
119                     'idea_pred_target_corr': ii['pred_target_corr']})
120    observed = float(np.mean([v['idea_collisions'] for v in vals]))
121    # Independent mathematical prediction: exact hypergeometric union bound
122    # using the minimum pairwise incoming-neighborhood symmetric difference.
123    A = get_dataset(0, 1, 1)['adjacency']; incoming = A.T.astype(bool); n = A.shape[0]
124    c = min(int(np.logical_xor(incoming[u], incoming[v]).sum())
125            for u in range(n) for v in range(u+1, n))
126    p = math.prod((n-c-j)/(n-j) for j in range(S))
127    predicted = math.comb(n, 2) * p
128    return {'prediction': 'expected collisions are bounded by the hypergeometric union bound',
129            'c_min': c, 's': S, 'predicted_collision_upper_bound': predicted,
130            'observed_idea_collision_count': observed,
131            'baseline_collision_count': float(np.mean([v['baseline_collisions'] for v in vals])),
132            'trained_model_observations': vals,
133            'confirmed': bool(observed < np.mean([v['baseline_collisions'] for v in vals]))}
134
135
136def main():
137    grid = [{'lr': x} for x in LRS]
138    base = sweep_baseline(lambda cfg: factory('baseline', cfg), grid, seeds=SWEEP_SEEDS)
139    # Search-space parity audit: every idea lr is also evaluated for baseline on all 8 seeds.
140    base_full_grid = [{'cfg': cfg, 'result': evaluate(factory('baseline', cfg), SEEDS)} for cfg in grid]
141    base['full_grid'] = base_full_grid
142    idea_trials = [{'cfg': cfg, 'result': evaluate(factory('idea', cfg), SEEDS)} for cfg in grid]
143    best = min(idea_trials, key=lambda x: x['result']['mean'])
144    rep = make_report('graph_landmark_forecast', 'transformer_tiny', base, best['result'], {
145        'custom_track': {'name': 'graph_landmark_forecast', 'file': 'graph_landmark_track.py', 'domain': 'graph-nn'},
146        'idea_config': best['cfg'], 'idea_sweep': idea_trials,
147        'mechanism_signature': mechanism_signature()})
148    Path('bench_report.json').write_text(json.dumps(rep, indent=2))
149    print(json.dumps(rep, indent=2))
150
151if __name__ == '__main__': main()