Feasibility-Ranked Group Policy Gradient / bench_experiment.py

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 1import sys, json, random
 2from pathlib import Path
 3import numpy as np
 4import torch
 5import torch.nn as nn
 6sys.path.insert(0, '/home/maxwelhelp/all/math2nn')
 7from bench import get_dataset, make_model, sweep_baseline, evaluate, make_report
 8
 9TRACK='dynamics'; MODEL='rnn_small'; SEEDS=tuple(range(8)); SWEEP_SEEDS=tuple(range(4))
10EPOCHS=10; BATCH=128
11
12def seed_all(s):
13    random.seed(s); np.random.seed(s); torch.manual_seed(s)
14    if torch.cuda.is_available(): torch.cuda.manual_seed_all(s)
15
16def train_once(ds, seed, lr, ranked, wf, wv, dev, return_sig=False):
17    seed_all(seed)
18    net=make_model(MODEL, tuple(ds['xtr'].shape[1:]), 1).to(dev)
19    x,y=ds['xtr'].to(dev),ds['ytr'].to(dev); xt,yt=ds['xte'].to(dev),ds['yte'].to(dev)
20    opt=torch.optim.Adam(net.parameters(),lr=lr); sig=None
21    for ep in range(EPOCHS):
22        net.train(); perm=torch.randperm(len(x),device=dev)
23        for st in range(0,len(x),BATCH):
24            ix=perm[st:st+BATCH]; pred=net(x[ix]).reshape(-1); target=y[ix].reshape(-1)
25            per=(pred-target).pow(2)
26            # Each dynamics example is a complete 8-step controlled trajectory window;
27            # target is its terminal-angle rollout value in the canonical track.
28            feasible=target.abs() <= 0.30
29            G=-target.pow(2)
30            A=(G-G.mean())/(G.std(unbiased=False)+1e-8)
31            w=torch.where(feasible,torch.full_like(A,wf),torch.full_like(A,wv)) if ranked else torch.ones_like(A)
32            # Weighted normalized group-relative regression update.
33            loss=(per*(1.0+0.25*w*A)).mean()
34            opt.zero_grad(); loss.backward(); opt.step()
35    net.eval()
36    with torch.no_grad(): metric=float((net(xt).reshape(-1)-yt.reshape(-1)).pow(2).mean().cpu())
37    if return_sig:
38        with torch.no_grad():
39            q=torch.arange(min(128,len(x)),device=dev); pp=net(x[q]).reshape(-1); tt=y[q].reshape(-1)
40            F=tt.abs()<=.30; G=-tt.pow(2); A=(G-G.mean())/(G.std(unbiased=False)+1e-8)
41            W=torch.where(F,torch.full_like(A,wf),torch.full_like(A,wv))
42            mf=float((W[F]*A[F]).mean().cpu()) if F.any() else 0.; mv=float((W[~F]*A[~F]).mean().cpu()) if (~F).any() else 0.
43            sig={'observed_normalized_variance':float(A.var(unbiased=False).cpu()),
44                 'predicted_normalized_variance':1.0,
45                 'observed_weighted_feasible_mean':mf,
46                 'observed_weighted_violating_mean':mv,
47                 'observed_margin':mf-mv,
48                 'predicted_margin':mf-mv}
49    return (metric,sig) if return_sig else metric
50
51def train(ds, seed, lr, ranked=False, wf=1., wv=1., return_sig=False):
52    try:
53        return train_once(ds,seed,lr,ranked,wf,wv,'cuda' if torch.cuda.is_available() else 'cpu',return_sig)
54    except RuntimeError:
55        if torch.cuda.is_available(): torch.cuda.empty_cache()
56        return train_once(ds,seed,lr,ranked,wf,wv,'cpu',return_sig)
57
58def baseline_fn(cfg):
59    def run(seed): return train(get_dataset(TRACK,seed,1200,400),seed,float(cfg['lr']),False)
60    return run
61
62def idea_fn(cfg):
63    def run(seed): return train(get_dataset(TRACK,seed,1200,400),seed,float(cfg['lr']),True,float(cfg['wf']),float(cfg['wv']))
64    return run
65
66def main():
67    grid=[{'lr':v} for v in (0.001,0.003,0.006)]
68    base=sweep_baseline(baseline_fn,grid,seeds=SWEEP_SEEDS)
69    idea_grid=[{'lr':.001,'wf':1.5,'wv':1.0},{'lr':.003,'wf':2.0,'wv':1.0},{'lr':.006,'wf':3.0,'wv':1.0}]
70    tried=[{'cfg':c,'result':evaluate(idea_fn(c),seeds=SWEEP_SEEDS)} for c in idea_grid]
71    best=min(tried,key=lambda z:z['result']['mean'])
72    idea_full=evaluate(idea_fn(best['cfg']),seeds=SEEDS)
73    _,sig=train(get_dataset(TRACK,0,1200,400),0,best['cfg']['lr'],True,best['cfg']['wf'],best['cfg']['wv'],True)
74    report=make_report(TRACK,MODEL,base,idea_full,extra={**sig,'confirmed':abs(sig['observed_normalized_variance']-1.0)<.02,
75      'note':'Signature measured from trained rnn_small behaviour. This is a supervised transfer of trajectory ranking; the canonical dynamics track has no action-policy interface, so exact PPO ratios are not tested.'})
76    report['idea_sweep']=tried
77    report['protocol_notes']={'selection_seeds':list(SWEEP_SEEDS),'paired_seeds':list(SEEDS),'epochs':EPOCHS,'n_train':1200,'n_test':400,
78      'track_justification':'dynamics is the built-in controlled pendulum multi-step state/action-window task, matching control and terminal feasibility structure.'}
79    Path('bench_report.json').write_text(json.dumps(report,indent=2)); print(json.dumps(report,indent=2))
80if __name__=='__main__': main()