waxal2026-backup / phase2_corrected /code /multi_rescore_v3.py
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#!/usr/bin/env python3
"""RESCORING v3 : ajoute (a) les monolingues lin comme rescoreurs (bons chemins),
(b) un TERME DE LONGUEUR — les scores etant des sommes de log-probs, ils penalisent
structurellement les hypotheses longues, ce qui peut expliquer une part de l'ecart a l'oracle.
score(h) = ac_cont(h) + lm_kenlm(h) + somme_i w_i*ac_i(h) + gamma*nb_mots(h)
"""
import json
import os
import pickle
import jiwer
import numpy as np
import soundfile as sf
import torch
from multiprocessing import Pool
from pyctcdecode import build_ctcdecoder
from transformers import AutoModelForCTC, AutoProcessor
M1 = "/root/models/joint_cont_best"
ARPA = "/scratch/lm/lin_5g.arpa"
NBEST = 10
R = "/scratch/restore"
RESCORERS = [
("cont2", "/root/models/joint_cont2_best"),
("lin_s4", "/root/models/lin_s4_best"),
("lin_r2", R + "/lin_r2_best"),
]
def comb(refs, hyps):
pr = [(r, h) for r, h in zip(refs, hyps) if r.strip()]
a = [x for x, _ in pr]
b = [y for _, y in pr]
w = jiwer.wer(a, b)
c = jiwer.cer(a, b)
return w, c, 0.5 * w + 0.5 * c
def encode_for(tok, text):
v = tok.get_vocab()
delim = getattr(tok, "word_delimiter_token", "|")
s = text.replace(" ", delim)
keep = "".join(c for c in s if c in v)
if not keep:
keep = "".join(c for c in text.lower().replace(" ", delim) if c in v)
return [v[c] for c in keep if v[c] != tok.pad_token_id]
def ctc_score(logp, ids, blank):
T = logp.shape[0]
if not ids or len(ids) > T:
return -1e9
lp = torch.from_numpy(logp).unsqueeze(1)
loss = torch.nn.functional.ctc_loss(
lp, torch.tensor(ids).unsqueeze(0), torch.tensor([T]), torch.tensor([len(ids)]),
blank=blank, reduction="sum", zero_infinity=True)
return -float(loss)
def compute_logits(model_dir, rows):
proc = AutoProcessor.from_pretrained(model_dir)
m = AutoModelForCTC.from_pretrained(model_dir, dtype=torch.float32).cuda().eval()
out = []
with torch.inference_mode():
for i in range(0, len(rows), 4):
b = rows[i:i + 4]
au = [sf.read(r["audio"], dtype="float32")[0] for r in b]
x = proc(au, sampling_rate=16000, return_tensors="pt", padding=True)
x = {k: v.cuda() for k, v in x.items()}
lg = m(**x).logits.log_softmax(-1).float().cpu().numpy()
for j in range(len(b)):
out.append(lg[j])
del m
torch.cuda.empty_cache()
return proc, out
def main():
rows = [json.loads(l) for l in open("/root/devhard/devhard_linsna.jsonl", encoding="utf-8")]
sub = [r for r in rows if r["lang"] == "lin"]
refs = [r["text"] for r in sub]
L1 = pickle.load(open("/scratch/lm/logits_lin.pkl", "rb"))
tok = AutoProcessor.from_pretrained(M1).tokenizer
v = tok.get_vocab()
lab = [None] * len(v)
for t, i in v.items():
lab[i] = t
lab[tok.word_delimiter_token_id] = " "
lab[tok.unk_token_id] = "⁇"
lab[tok.pad_token_id] = ""
greedy = [" ".join(tok.decode(l.argmax(-1)).replace("|", " ").split()) for l in L1]
def cc(h, g):
return (g[:1] + h[1:]) if (h and g) else h
dec = build_ctcdecoder(lab, kenlm_model_path=ARPA, alpha=0.5, beta=0.5,
lm_score_boundary=False)
with Pool(8) as p:
allbeams = dec.decode_beams_batch(p, L1, beam_width=64)
with Pool(8) as p:
db = [" ".join(x.split()) for x in dec.decode_batch(p, L1, beam_width=64)]
_, _, REF = comb(refs, [cc(h, g) for h, g in zip(db, greedy)])
print("reference: %.4f" % REF, flush=True)
cands, AC1, LM, NW = [], [], [], []
for i, bs in enumerate(allbeams):
c = [" ".join(b[0].split()) for b in bs[:NBEST]]
a = [(b[3] if len(b) > 3 else 0.0) for b in bs[:NBEST]]
l = [((b[4] - b[3]) if len(b) > 4 else 0.0) for b in bs[:NBEST]]
if db[i] not in c:
c.append(db[i])
a.append(ctc_score(L1[i], encode_for(tok, db[i]), tok.pad_token_id))
l.append(float(np.mean(l)) if l else 0.0)
cands.append(c)
AC1.append(np.array(a))
LM.append(np.array(l))
NW.append(np.array([float(len(x.split())) for x in c]))
SC = {}
for tag, mdl in RESCORERS:
if not os.path.isdir(mdl):
print("%-8s ABSENT %s" % (tag, mdl), flush=True)
continue
proc, LG = compute_logits(mdl, sub)
t2 = proc.tokenizer
SC[tag] = [np.array([ctc_score(LG[i], encode_for(t2, x), t2.pad_token_id)
for x in cands[i]]) for i in range(len(cands))]
print("%-8s scores OK (|V|=%d)" % (tag, len(t2.get_vocab())), flush=True)
def evaluate(W, gamma=0.0):
hyps = []
for i in range(len(cands)):
tot = AC1[i] + LM[i] + gamma * NW[i]
for t, w in W.items():
if w:
tot = tot + w * SC[t][i]
hyps.append(cc(cands[i][int(np.argmax(tot))], greedy[i]))
return comb(refs, hyps)[2]
print("\n--- (a) rescoreurs solo ---", flush=True)
for tag in SC:
bb = (9.0, 0.0)
for w in (0.3, 0.5, 1.0, 1.5, 2.5, 4.0):
m = evaluate({tag: w})
if m < bb[0]:
bb = (m, w)
print(" %-8s %.4f (w=%.1f) %+.4f" % (tag, bb[0], bb[1], bb[0] - REF), flush=True)
print("\n--- (b) terme de longueur seul (gamma), sans rescoreur ---", flush=True)
for gm in (-2.0, -1.0, 0.0, 1.0, 2.0, 4.0, 8.0):
print(" gamma=%+5.1f : %.4f (%+.4f)" % (gm, evaluate({}, gm), evaluate({}, gm) - REF), flush=True)
print("\n--- (c) cont2 + longueur ---", flush=True)
best = (9.0, None, None)
for w in (1.0, 1.5, 2.5):
for gm in (0.0, 1.0, 2.0, 4.0, 8.0):
m = evaluate({"cont2": w}, gm)
if m < best[0]:
best = (m, w, gm)
print(" cont2=%.1f gamma=%+5.1f : %.4f (%+.4f)" % (w, gm, m, m - REF), flush=True)
print("\nBEST_V3 %.4f cont2=%s gamma=%s (ref %.4f, gain %+.4f)"
% (best[0], best[1], best[2], REF, best[0] - REF), flush=True)
json.dump({"combine": best[0], "cont2": best[1], "gamma": best[2], "ref": REF},
open("/root/multi_v3.json", "w"))
print("V3_DONE", flush=True)
if __name__ == "__main__":
main()