Fix chosen-token regularization
This commit is contained in:
@@ -259,7 +259,8 @@ finetune_shuffle_seed: 666
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# 0 = off; 0.9 strongly downsamples overrepresented rule violations
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# (this is useful because the raw generated dataset is typically very skewed)
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ftpo_sample_rejected_regularisation_strength: 0.8
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ftpo_sample_chosen_regularisation_strength: 0.2
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# 0 = off; positive values trim globally overrepresented chosen-token slots
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ftpo_sample_chosen_regularisation_strength: 0.0
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ftpo_sample_min_chosen_tokens: 4 # filter out ftpo samples that have fewer than this number in the chosen tokens list
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# ── FTPO-specific hyper-parameters ─────────────────────────────────────────
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@@ -265,7 +265,8 @@ finetune_shuffle_seed: 666
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# 0 = off; 0.9 strongly downsamples overrepresented rule violations
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# (this is useful because the raw generated dataset is typically very skewed)
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ftpo_sample_rejected_regularisation_strength: 0.8
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ftpo_sample_chosen_regularisation_strength: 0.2
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# 0 = off; positive values trim globally overrepresented chosen-token slots
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ftpo_sample_chosen_regularisation_strength: 0.0
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ftpo_sample_min_chosen_tokens: 4 # filter out ftpo samples that have fewer than this number in the chosen tokens list
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@@ -265,7 +265,8 @@ finetune_shuffle_seed: 666
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# 0 = off; 0.9 strongly downsamples overrepresented rule violations
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# (this is useful because the raw generated dataset is typically very skewed)
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ftpo_sample_rejected_regularisation_strength: 0.7
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ftpo_sample_chosen_regularisation_strength: 0.2
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# 0 = off; positive values trim globally overrepresented chosen-token slots
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ftpo_sample_chosen_regularisation_strength: 0.0
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ftpo_sample_min_chosen_tokens: 3 # filter out ftpo samples that have fewer than this number in the chosen tokens list
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@@ -259,7 +259,8 @@ finetune_shuffle_seed: 666
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# 0 = off; 0.9 strongly downsamples overrepresented rule violations
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# (this is useful because the raw generated dataset is typically very skewed)
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ftpo_sample_rejected_regularisation_strength: 0.8
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ftpo_sample_chosen_regularisation_strength: 0.2
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# 0 = off; positive values trim globally overrepresented chosen-token slots
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ftpo_sample_chosen_regularisation_strength: 0.0
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ftpo_sample_min_chosen_tokens: 4 # filter out ftpo samples that have fewer than this number in the chosen tokens list
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# ── FTPO-specific hyper-parameters ─────────────────────────────────────────
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@@ -258,7 +258,8 @@ finetune_shuffle_seed: 666
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# 0 = off; 0.9 strongly downsamples overrepresented rule violations
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# (this is useful because the raw generated dataset is typically very skewed)
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ftpo_sample_rejected_regularisation_strength: 0.8
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ftpo_sample_chosen_regularisation_strength: 0.2
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# 0 = off; positive values trim globally overrepresented chosen-token slots
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ftpo_sample_chosen_regularisation_strength: 0.0
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ftpo_sample_min_chosen_tokens: 4 # filter out ftpo samples that have fewer than this number in the chosen tokens list
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@@ -258,7 +258,8 @@ finetune_shuffle_seed: 666
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# 0 = off; 0.9 strongly downsamples overrepresented rule violations
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# (this is useful because the raw generated dataset is typically very skewed)
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ftpo_sample_rejected_regularisation_strength: 0.6
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ftpo_sample_chosen_regularisation_strength: 0.2
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# 0 = off; positive values trim globally overrepresented chosen-token slots
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ftpo_sample_chosen_regularisation_strength: 0.0
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ftpo_sample_min_chosen_tokens: 4 # filter out ftpo samples that have fewer than this number in the chosen tokens list
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@@ -258,7 +258,8 @@ finetune_shuffle_seed: 666
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# 0 = off; 0.9 strongly downsamples overrepresented rule violations
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# (this is useful because the raw generated dataset is typically very skewed)
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ftpo_sample_rejected_regularisation_strength: 0.8
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ftpo_sample_chosen_regularisation_strength: 0.2
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# 0 = off; positive values trim globally overrepresented chosen-token slots
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ftpo_sample_chosen_regularisation_strength: 0.0
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ftpo_sample_min_chosen_tokens: 4 # filter out ftpo samples that have fewer than this number in the chosen tokens list
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@@ -16,6 +16,82 @@ logger = logging.getLogger(__name__)
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_WATCH = [" nodded", " leaned"]
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def _chosen_target_quotas(
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chosen_counts: Counter[str],
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strength: float,
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) -> dict[str, int]:
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"""Return per-token occurrence caps for chosen-token regularisation."""
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if not chosen_counts or strength <= 0:
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return dict(chosen_counts)
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# Prevent the largest outliers from dominating the distribution before
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# applying the smoother median-threshold regularisation.
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if len(chosen_counts) >= 10:
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cap_value = sorted(chosen_counts.values(), reverse=True)[9]
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capped = {
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token: min(count, cap_value)
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for token, count in chosen_counts.items()
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}
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else:
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capped = dict(chosen_counts)
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median = float(np.median(list(capped.values())))
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return {
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token: int(round(
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count
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if count <= median
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else count * (median / count) ** strength
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))
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for token, count in capped.items()
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}
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def _trim_chosen_to_quotas(
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rows: list[dict],
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quotas: dict[str, int],
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rng: np.random.Generator,
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) -> list[dict]:
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"""Uniformly retain chosen-token occurrences up to their global quotas."""
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counts = Counter(
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token
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for row in rows
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for token in (row.get("multi_chosen_decoded") or [])
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)
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if all(quotas.get(token, count) >= count for token, count in counts.items()):
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return [dict(row) for row in rows]
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# Randomise both row and slot traversal so quota allocation does not
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# systematically favour early examples or a token's probability rank.
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seen: Counter[str] = Counter()
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trimmed: list[dict | None] = [None] * len(rows)
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for row_idx_raw in rng.permutation(len(rows)):
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row_idx = int(row_idx_raw)
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row = rows[row_idx]
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decoded = row.get("multi_chosen_decoded") or []
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keep: set[int] = set()
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for slot_idx_raw in rng.permutation(len(decoded)):
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slot_idx = int(slot_idx_raw)
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token = decoded[slot_idx]
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if seen[token] < max(0, quotas.get(token, counts[token])):
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keep.add(slot_idx)
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seen[token] += 1
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new_row = dict(row)
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new_row["multi_chosen_decoded"] = [
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token for slot_idx, token in enumerate(decoded) if slot_idx in keep
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]
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raw = row.get("multi_chosen_raw")
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if isinstance(raw, list) and len(raw) == len(decoded):
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new_row["multi_chosen_raw"] = [
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token for slot_idx, token in enumerate(raw) if slot_idx in keep
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]
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trimmed[row_idx] = new_row
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return [row for row in trimmed if row is not None]
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def load_ftpo_multi_dataset(
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path: Path,
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tokenizer,
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@@ -108,24 +184,10 @@ def load_ftpo_multi_dataset(
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_log_top(chosen_cts_orig, "ORIGINAL CHOSEN TOKENS")
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# Trim the peak: cap top tokens to match the 10th highest count
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if len(chosen_cts_orig) >= 10:
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top_counts = sorted(chosen_cts_orig.values(), reverse=True)
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cap_value = top_counts[9] # 10th highest count
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chosen_cts_capped = Counter()
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for tok, cnt in chosen_cts_orig.items():
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chosen_cts_capped[tok] = min(cnt, cap_value)
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else:
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chosen_cts_capped = chosen_cts_orig.copy()
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# Now calculate regularization on the capped distribution
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med_chosen = float(np.median(list(chosen_cts_capped.values())))
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w_chosen = {tok: 1.0 if c <= med_chosen
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else (med_chosen / c) ** chosen_reg_strength
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for tok, c in chosen_cts_capped.items()}
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tgt_chosen = {tok: int(round(c * w_chosen.get(tok, 1.0)))
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for tok, c in chosen_cts_capped.items()}
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tgt_chosen = _chosen_target_quotas(
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chosen_cts_orig,
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chosen_reg_strength,
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)
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# Log the target quotas
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quota_items = sorted(tgt_chosen.items(), key=lambda x: x[1], reverse=True)[:20]
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@@ -137,7 +199,13 @@ def load_ftpo_multi_dataset(
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_WATCH[1], tgt_chosen.get(_WATCH[1], 0), chosen_cts_orig.get(_WATCH[1], 0),
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)
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_log_top(Counter(r["rejected_decoded"] for r in rows), "POST-CHOSEN")
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rows = _trim_chosen_to_quotas(rows, tgt_chosen, rng)
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chosen_cts_trimmed = Counter(
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token
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for row in rows
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for token in (row["multi_chosen_decoded"] or [])
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)
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_log_top(chosen_cts_trimmed, "POST-CHOSEN")
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# ────────────────────────────────────────────────────────────────
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# 3️⃣ Apply min_chosen_tokens row filter
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@@ -206,6 +274,13 @@ def load_ftpo_multi_dataset(
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rows = selected
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final_chosen_counts = Counter(
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token
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for row in rows
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for token in (row["multi_chosen_decoded"] or [])
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)
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_log_top(final_chosen_counts, "FINAL CHOSEN TOKENS")
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# ── Dump the final row subset exactly as it was read (no tokenisation) ──
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if experiment_run_dir is not None:
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ts = datetime.now(timezone.utc).astimezone()\
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154
utils/test_dataset_helpers.py
Normal file
154
utils/test_dataset_helpers.py
Normal file
@@ -0,0 +1,154 @@
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import json
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import tempfile
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import unittest
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from collections import Counter
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from pathlib import Path
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import numpy as np
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from utils.dataset_helpers import (
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_chosen_target_quotas,
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_trim_chosen_to_quotas,
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load_ftpo_multi_dataset,
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)
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def _counts(rows):
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return Counter(
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token
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for row in rows
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for token in row["multi_chosen_decoded"]
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)
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class _Tokenized:
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def __init__(self, input_ids):
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self.input_ids = input_ids
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class _FakeTokenizer:
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truncation_side = "right"
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def __call__(self, text, **_kwargs):
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def encode(value):
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if value.startswith("context-"):
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return [1, 2]
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return [100 + sum(value.encode("utf-8"))]
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if isinstance(text, list):
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return _Tokenized([encode(value) for value in text])
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return _Tokenized(encode(text))
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class ChosenRegularisationTests(unittest.TestCase):
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def test_zero_strength_disables_all_trimming(self):
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counts = Counter({f"token-{i}": 20 - i for i in range(12)})
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self.assertEqual(_chosen_target_quotas(counts, 0), dict(counts))
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def test_positive_strength_caps_and_regularises_outliers(self):
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counts = Counter({f"token-{i}": 100 - 5 * i for i in range(12)})
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quotas = _chosen_target_quotas(counts, 0.2)
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tenth_highest = sorted(counts.values(), reverse=True)[9]
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self.assertLess(quotas["token-0"], counts["token-0"])
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self.assertLessEqual(quotas["token-0"], tenth_highest)
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self.assertEqual(quotas["token-11"], counts["token-11"])
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def test_trimming_enforces_quotas_and_keeps_raw_fields_aligned(self):
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rows = [
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{
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"multi_chosen_decoded": [" common", " rare-a", " common"],
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"multi_chosen_raw": ["raw-common-1", "raw-rare-a", "raw-common-2"],
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},
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{
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"multi_chosen_decoded": [" common", " rare-b"],
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"multi_chosen_raw": ["raw-common-3", "raw-rare-b"],
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},
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]
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quotas = {" common": 2, " rare-a": 1, " rare-b": 1}
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trimmed = _trim_chosen_to_quotas(
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rows, quotas, np.random.default_rng(3407)
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)
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self.assertEqual(_counts(trimmed), Counter(quotas))
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for row in trimmed:
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self.assertEqual(
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len(row["multi_chosen_decoded"]),
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len(row["multi_chosen_raw"]),
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)
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# The helper does not mutate the source rows.
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self.assertEqual(rows[0]["multi_chosen_decoded"].count(" common"), 2)
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def test_trimming_is_reproducible(self):
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rows = [
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{
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"multi_chosen_decoded": [" common", f" unique-{i}"],
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"multi_chosen_raw": [" common", f" unique-{i}"],
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}
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for i in range(20)
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]
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quotas = {" common": 5, **{f" unique-{i}": 1 for i in range(20)}}
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first = _trim_chosen_to_quotas(
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rows, quotas, np.random.default_rng(123)
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)
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second = _trim_chosen_to_quotas(
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rows, quotas, np.random.default_rng(123)
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)
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self.assertEqual(first, second)
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self.assertEqual(_counts(first)[" common"], 5)
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def test_minimum_filter_applies_after_trimming(self):
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rows = [
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{"multi_chosen_decoded": [" common", " keep"]},
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{"multi_chosen_decoded": [" common", " other"]},
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]
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trimmed = _trim_chosen_to_quotas(
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rows,
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{" common": 1, " keep": 1, " other": 1},
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np.random.default_rng(7),
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)
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surviving = [
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row for row in trimmed if len(row["multi_chosen_decoded"]) >= 2
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]
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self.assertEqual(len(surviving), 1)
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def test_loader_filters_rows_after_applying_chosen_quotas(self):
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rows = [
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{
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"context_with_chat_template": f"context-{i}",
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"rejected_decoded": " reject",
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"multi_chosen_decoded": [" common", f" unique-{i}"],
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"multi_chosen_raw": ["raw-common", f"raw-unique-{i}"],
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}
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for i in range(4)
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]
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with tempfile.TemporaryDirectory() as tmp_dir:
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path = Path(tmp_dir) / "ftpo.jsonl"
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with path.open("w", encoding="utf-8") as handle:
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for row in rows:
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handle.write(json.dumps(row) + "\n")
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dataset = load_ftpo_multi_dataset(
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path,
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_FakeTokenizer(),
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chosen_reg_strength=1.0,
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min_chosen_tokens=2,
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num_proc=1,
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)
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# " common" is trimmed from four occurrences to one, so only its
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# containing row still meets the two-chosen-token minimum.
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self.assertEqual(len(dataset), 1)
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self.assertEqual(len(dataset[0]["chosen_ids"]), 2)
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if __name__ == "__main__":
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unittest.main()
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@@ -110,7 +110,7 @@ def load_and_prepare_dataset(config: dict, experiment_run_dir: Path, tokenizer:
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# balance *rejected* tokens
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rejected_reg_strength = config.get("ftpo_sample_rejected_regularisation_strength", 0.8),
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# balance *chosen* tokens
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chosen_reg_strength = config.get("ftpo_sample_chosen_regularisation_strength", 0.2),
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chosen_reg_strength = config.get("ftpo_sample_chosen_regularisation_strength", 0.0),
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# hard floor on |chosen|
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min_chosen_tokens = config.get("ftpo_sample_min_chosen_tokens", 3),
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# overall training-set cap (used for per-token quotas too)
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@@ -158,7 +158,7 @@ def load_and_prepare_dataset(config: dict, experiment_run_dir: Path, tokenizer:
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experiment_run_dir = experiment_run_dir,
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max_seq_len = max_seq_length,
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rejected_reg_strength = config.get("ftpo_sample_rejected_regularisation_strength", 0.8),
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chosen_reg_strength = config.get("ftpo_sample_chosen_regularisation_strength", 0.2),
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chosen_reg_strength = config.get("ftpo_sample_chosen_regularisation_strength", 0.0),
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min_chosen_tokens = config.get("ftpo_sample_min_chosen_tokens", 3),
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max_train_examples = config.get("finetune_max_train_examples"),
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)
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@@ -247,7 +247,7 @@ def load_and_prepare_dataset(config: dict, experiment_run_dir: Path, tokenizer:
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experiment_run_dir = experiment_run_dir,
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max_seq_len = max_seq_length,
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rejected_reg_strength = config.get("ftpo_sample_rejected_regularisation_strength", 0.8),
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chosen_reg_strength = config.get("ftpo_sample_chosen_regularisation_strength", 0.2),
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chosen_reg_strength = config.get("ftpo_sample_chosen_regularisation_strength", 0.0),
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min_chosen_tokens = config.get("ftpo_sample_min_chosen_tokens", 3),
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max_train_examples = config.get("finetune_max_train_examples"),
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)
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@@ -299,7 +299,7 @@ def load_and_prepare_dataset(config: dict, experiment_run_dir: Path, tokenizer:
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experiment_run_dir = experiment_run_dir,
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max_seq_len = max_seq_length,
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rejected_reg_strength = config.get("ftpo_sample_rejected_regularisation_strength", 0.8),
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chosen_reg_strength = config.get("ftpo_sample_chosen_regularisation_strength", 0.2),
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chosen_reg_strength = config.get("ftpo_sample_chosen_regularisation_strength", 0.0),
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min_chosen_tokens = config.get("ftpo_sample_min_chosen_tokens", 3),
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max_train_examples = config.get("finetune_max_train_examples"),
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)
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Block a user