Upload 5p.py

5p.py

@@ -0,0 +1,1003 @@
+#!/usr/bin/env python3
+# 5apg.py — AR-only trainer/decoder (DeepSeek tokenizer)
+# Fresh-start safe, AMP dtype auto, OOM backoff, progressive block growth.
+# Sampling: repetition/presence/frequency penalties, top-k/top-p/min-p, greedy, no-repeat-ngrams.
+# Checkpoints: time-based and step-based (monotonic). Resume respects interval.
+# FP8: --fp8-only [--fp8-fallback] attempts float8_e4m3fn autocast, otherwise bf16/FP16.
+# Chinchilla-style target token calc uses ALL enabled params (core + AR head).
+# Robust streaming: retries, dataset fallbacks, dataset:config, and local JSONL support.
+# Chat SFT: --chat uses tokenizer.apply_chat_template on records with {role, content} lists.
+
+from __future__ import annotations
+import argparse, json, math, pathlib, random, time, os, sys
+from contextlib import nullcontext
+from typing import Dict, Any, List, Optional, Tuple
+
+import torch
+import torch.nn as nn
+import torch.nn.functional as F
+from datasets import load_dataset, DownloadConfig
+from transformers import AutoTokenizer, logging as hf_log
+from tqdm.auto import tqdm
+
+# ───────────────────────── Globals ─────────────────────────
+hf_log.set_verbosity_error()
+DEV = torch.device("cuda" if torch.cuda.is_available() else "cpu")
+torch.backends.cuda.matmul.allow_tf32 = True
+try:
+    torch.set_float32_matmul_precision("high")
+except Exception:
+    pass
+
+# ───────────────────────── Determinism ─────────────────────────
+def set_seed(seed: int | None):
+    if seed is None:
+        return
+    random.seed(seed)
+    torch.manual_seed(seed)
+    if torch.cuda.is_available():
+        torch.cuda.manual_seed_all(seed)
+    try:
+        import numpy as _np
+        _np.random.seed(seed)
+    except Exception:
+        pass
+
+# Tokenizer (default DeepSeek V3.2 Exp)
+TOKENIZER_ID = os.environ.get("TOKENIZER_ID", "deepseek-ai/DeepSeek-V3.2-Exp")
+tok = AutoTokenizer.from_pretrained(TOKENIZER_ID, use_fast=True, trust_remote_code=True)
+if tok.pad_token is None:
+    tok.add_special_tokens({"pad_token": "[PAD]"})
+VOCAB = max(tok.get_vocab().values()) + 1
+BLANK = tok.pad_token_id
+EOS = tok.eos_token_id if tok.eos_token_id is not None else tok.sep_token_id
+
+PRESETS: Dict[str, Dict[str, int]] = {
+    "small":   dict(d=512, layers=8,  heads=16, rank=64),
+    "smallx2": dict(d=512, layers=16, heads=16, rank=64),
+    "base":    dict(d=768, layers=12, heads=24, rank=96),
+    # requested: base version with 17 layers
+    "base17":  dict(d=768, layers=17, heads=24, rank=96),
+}
+
+DEFAULT_BLOCK = 576
+LR_CORE, LR_HEAD = 5e-5, 2e-4
+DEFAULT_SAVE_SEC = 24 * 3600
+CKDIR = pathlib.Path("ckpts_joint")
+
+# Defaults for automatic after-SFT if user only sets --after_sft_steps
+DEFAULT_AFTER_SFT_SOURCES = "mlabonne/opc-sft-stage2-chat,HuggingFaceH4/ultrachat_200k"
+DEFAULT_AFTER_SFT_BLOCK = 1120
+
+# New: default pretrain sources (replaces SlimPajama/C4)
+DEFAULT_PRETRAIN_SOURCES = "HuggingFaceFW/fineweb-edu,togethercomputer/RedPajama-Data-1T,oscar-corpus/OSCAR-2201:en"
+
+# ───────────────────────── Utilities ─────────────────────────
+def rng_state():
+    if DEV.type == "cuda":
+        try:
+            return torch.cuda.get_rng_state(DEV)
+        except TypeError:
+            return torch.cuda.get_rng_state()
+    return torch.get_rng_state()
+
+def _is_probably_ckpt(path: pathlib.Path) -> bool:
+    try:
+        return path.is_file() and path.suffix == ".pt" and not path.name.endswith(".pt.tmp") and path.stat().st_size > (1<<20)
+    except Exception:
+        return False
+
+def _resolve_ckpt(path: pathlib.Path) -> pathlib.Path | None:
+    try:
+        if path.is_dir():
+            cands = sorted([p for p in path.glob("*.pt") if _is_probably_ckpt(p)],
+                           key=lambda p: p.stat().st_mtime, reverse=True)
+            return cands[0] if cands else None
+        if path.suffix == ".tmp":
+            solid = path.with_suffix("")
+            return solid if _is_probably_ckpt(solid) else _resolve_ckpt(path.parent)
+        return path if _is_probably_ckpt(path) else _resolve_ckpt(path.parent)
+    except Exception:
+        return None
+
+def _try_load(path: pathlib.Path, map_location="cpu"):
+    try:
+        return torch.load(path, map_location="cpu")
+    except Exception as e:
+        print(f"[ckpt-skip] {path} not usable: {e}")
+        return None
+
+# ───────────────────────── AMP helper ─────────────────────────
+try:
+    from torch.amp import autocast as _ac, GradScaler
+except ImportError:
+    from torch.cuda.amp import autocast as _ac, GradScaler
+
+def _supports_fp8() -> bool:
+    return hasattr(torch, "float8_e4m3fn")
+
+def _auto_amp_dtype(prefer_fp8: bool = False):
+    if DEV.type != "cuda":
+        return torch.float32
+    if prefer_fp8 and _supports_fp8():
+        return torch.float8_e4m3fn
+    try:
+        if torch.cuda.is_bf16_supported():
+            return torch.bfloat16
+        return torch.float16
+    except Exception:
+        return torch.float16
+
+def amp(enabled: bool, prefer_fp8: bool = False):
+    if not (enabled and DEV.type == "cuda"):
+        return nullcontext()
+    return _ac(device_type="cuda", dtype=_auto_amp_dtype(prefer_fp8=prefer_fp8))
+
+# ───────────────────────── Chat helpers ─────────────────────────
+def _coerce_role(r: str) -> str:
+    r = (r or "").lower()
+    if r in {"user", "human", "customer", "questioner"}:
+        return "user"
+    if r in {"assistant", "gpt", "bot", "agent", "answerer"}:
+        return "assistant"
+    if r in {"system", "context", "instruction"}:
+        return "system"
+    return r or "user"
+
+def _render_chat_text_from_ex(ex: dict, messages_key: str, add_generation_prompt: bool) -> Optional[str]:
+    msgs = ex.get(messages_key)
+    if msgs is None:
+        for alt in ("conversations", "dialog", "turns"):
+            if isinstance(ex.get(alt), list):
+                msgs = ex[alt]
+                break
+    if isinstance(msgs, list) and msgs and isinstance(msgs[0], dict):
+        try:
+            norm = []
+            for m in msgs:
+                role = _coerce_role(m.get("role", "")); content = m.get("content", m.get("text", ""))
+                if not isinstance(content, str):
+                    continue
+                norm.append({"role": role, "content": content})
+            if not norm:
+                return None
+            return tok.apply_chat_template(norm, tokenize=False, add_generation_prompt=add_generation_prompt)
+        except Exception:
+            return None
+    for a, b in (("prompt", "response"), ("instruction", "output"), ("question", "answer")):
+        if isinstance(ex.get(a), str) and isinstance(ex.get(b), str):
+            return f"User: {ex[a]}\nAssistant: {ex[b]}"
+    return None
+
+# ───────────────────────── Robust streaming data ─────────────────────────
+def _open_stream_one(ds_name: str, seed: int):
+    if ":" in ds_name:
+        base, config = ds_name.split(":", 1)
+    else:
+        base, config = ds_name, None
+    dc = DownloadConfig(max_retries=5, use_etag=True, resume_download=True)
+    if base == "json":
+        if not config:
+            raise ValueError("Use 'json:/path/to/file.jsonl' or glob like 'json:/data/*.jsonl'")
+        data_files = {"train": config}
+        ds = load_dataset("json", data_files=data_files, split="train", streaming=True, download_config=dc)
+    else:
+        if config:
+            ds = load_dataset(base, config, split="train", streaming=True, download_config=dc)
+        else:
+            ds = load_dataset(base, split="train", streaming=True, download_config=dc)
+    ds = ds.shuffle(buffer_size=10_000, seed=seed)
+    return iter(ds)
+
+def token_stream(args, target: int, seed: int = 42, max_retries: int = 999, *,
+                 source: Optional[str] = None, chat: Optional[bool] = None,
+                 chat_messages_key: Optional[str] = None, sft_add_generation_prompt: Optional[bool] = None,
+                 dataset_field_text: Optional[str] = None):
+    ds_names = source if source is not None else args.source
+    sources = [s.strip() for s in ds_names.split(",") if s.strip()]
+    if not sources:
+        # Default replaced: use the three stable sources by default
+        sources = [s.strip() for s in DEFAULT_PRETRAIN_SOURCES.split(",") if s.strip()]
+    use_chat = args.chat if chat is None else chat
+    msg_key  = args.chat_messages_key if chat_messages_key is None else chat_messages_key
+    add_gen  = args.sft_add_generation_prompt if sft_add_generation_prompt is None else sft_add_generation_prompt
+    text_key = args.dataset_field_text if dataset_field_text is None else dataset_field_text
+
+    src_idx = 0; emitted = 0; it = None; attempts = 0; backoff_base = 2.0
+    while emitted < target:
+        try:
+            if it is None:
+                it = _open_stream_one(sources[src_idx], seed)
+            ex = next(it)
+            text = None
+            if isinstance(ex, dict):
+                if use_chat:
+                    text = _render_chat_text_from_ex(ex, msg_key, add_gen)
+                if text is None:
+                    if text_key and isinstance(ex.get(text_key), str):
+                        text = ex[text_key]
+                    elif isinstance(ex.get("text"), str):
+                        text = ex["text"]
+            if not isinstance(text, str):
+                attempts = 0; continue
+            enc = tok.encode(text)
+            if EOS is not None and (len(enc) == 0 or enc[-1] != EOS):
+                enc.append(EOS)
+            for t in enc:
+                yield t; emitted += 1
+                if emitted >= target:
+                    return
+            attempts = 0
+        except StopIteration:
+            it = None; src_idx = (src_idx + 1) % len(sources)
+        except Exception as e:
+            attempts += 1
+            sleep_s = min(60.0, backoff_base ** min(attempts, 6))
+            print(f"[stream-retry] source={sources[src_idx]} attempts={attempts} sleep={sleep_s:.1f}s reason={type(e).__name__}", flush=True)
+            time.sleep(sleep_s); it = None
+            if attempts % 5 == 0 and len(sources) > 1:
+                src_idx = (src_idx + 1) % len(sources)
+            if attempts > max_retries:
+                raise
+
+# ───────────────────────── Relative positional bias (ALiBi) ─────────────────────────
+def _alibi_slopes(n_heads: int):
+    import math
+    def pow2slopes(n):
+        start = 2 ** (-2 ** -(math.log2(n) - 3))
+        ratio = start
+        return [start * (ratio ** i) for i in range(n)]
+    if math.log2(n_heads).is_integer():
+        vals = pow2slopes(n_heads)
+    else:
+        closest = 2 ** math.floor(math.log2(n_heads))
+        vals = pow2slopes(closest)
+        extra = pow2slopes(2 * closest)
+        vals += extra[0::2][: n_heads - closest]
+    return torch.tensor(vals, device=DEV).view(1, n_heads, 1, 1)
+
+def alibi_bias(n_heads: int, n_tokens: int):
+    i = torch.arange(n_tokens, device=DEV).view(1, 1, n_tokens, 1)
+    j = torch.arange(n_tokens, device=DEV).view(1, 1, 1, n_tokens)
+    dist = (j - i).clamp_min(0)
+    slopes = _alibi_slopes(n_heads)
+    return -slopes * dist
+
+# ───────────────────────── Model components ─────────────────────────
+class LowRankMHA(nn.Module):
+    def __init__(self, d: int, h: int, r: int, use_relpos: bool = True):
+        super().__init__()
+        assert d % h == 0, "d must be divisible by number of heads"
+        self.h, self.dk = h, d // h
+        self.use_relpos = use_relpos
+        self.q = nn.Linear(d, d, bias=False)
+        self.k = nn.Linear(d, d, bias=False)
+        self.v = nn.Linear(d, d, bias=False)
+        self.U = nn.Parameter(torch.randn(self.dk, r))
+        nn.init.orthogonal_(self.U)
+        self.proj = nn.Linear(h * r, d, bias=False)
+        self.drop = nn.Dropout(0.1)
+
+    def _proj(self, x):
+        B, N, _ = x.shape
+        return (x.view(B, N, self.h, self.dk).transpose(1, 2) @ self.U)
+
+    def forward(self, x: torch.Tensor, mask: Optional[torch.Tensor] = None,
+                rel_bias_tokens: Optional[int] = None,
+                kv_cache: Optional[Tuple[torch.Tensor, torch.Tensor]] = None,
+                use_cache: bool = False):
+        q = self._proj(self.q(x))
+        k_new = self._proj(self.k(x))
+        v_new = self._proj(self.v(x))
+
+        if kv_cache is None:
+            k, v = k_new, v_new
+        else:
+            k, v = kv_cache
+            if use_cache:
+                k = torch.cat([k, k_new], dim=2)
+                v = torch.cat([v, v_new], dim=2)
+
+        att = (q @ k.transpose(-1, -2)) / math.sqrt(self.dk)
+
+        if q.size(2) == k.size(2):
+            if self.use_relpos and rel_bias_tokens is not None:
+                att = att + alibi_bias(self.h, rel_bias_tokens)
+            if mask is not None:
+                att = att + mask
+
+        z = (att.softmax(-1) @ v).transpose(1, 2)
+        z = z.reshape(x.size(0), x.size(1), -1)
+        out = self.drop(self.proj(z))
+        return (out, (k, v)) if use_cache else out
+
+class Block(nn.Module):
+    def __init__(self, d: int, h: int, r: int):
+        super().__init__()
+        self.ln1, self.ln2 = nn.LayerNorm(d), nn.LayerNorm(d)
+        self.mha = LowRankMHA(d, h, r, use_relpos=True)
+        self.ff = nn.Sequential(nn.Linear(d, 4 * d), nn.ReLU(), nn.Linear(4 * d, d))
+
+    def forward(self, x: torch.Tensor, mask: Optional[torch.Tensor],
+                kv: Optional[Tuple[torch.Tensor, torch.Tensor]] = None,
+                use_cache: bool = False):
+        n = x.size(1)
+        if use_cache:
+            y, new_kv = self.mha(self.ln1(x), mask, rel_bias_tokens=n if mask is not None else None, kv_cache=kv, use_cache=True)
+            x = x + y
+            x = x + self.ff(self.ln2(x))
+            return x, new_kv
+        else:
+            x = x + self.mha(self.ln1(x), mask, rel_bias_tokens=n)
+            return x + self.ff(self.ln2(x))
+
+class Encoder(nn.Module):
+    def __init__(self, cfg: Dict[str, int]):
+        super().__init__()
+        d, l, h, r = cfg["d"], cfg["layers"], cfg["heads"], cfg["rank"]
+        self.emb = nn.Embedding(VOCAB, d)
+        self.blocks = nn.ModuleList([Block(d, h, r) for _ in range(l)])
+        self.ln = nn.LayerNorm(d)
+
+    def forward(self, ids: torch.Tensor, mask: Optional[torch.Tensor],
+                kv_caches: Optional[List[Optional[Tuple[torch.Tensor, torch.Tensor]]]] = None,
+                use_cache: bool = False):
+        x = self.emb(ids)
+        if not use_cache:
+            for blk in self.blocks:
+                x = blk(x, mask)
+            return self.ln(x)
+        new_kvs: List[Tuple[torch.Tensor, torch.Tensor]] = []
+        for i, blk in enumerate(self.blocks):
+            kv = kv_caches[i] if (kv_caches is not None) else None
+            x, kv_out = blk(x, mask, kv, use_cache=True)
+            new_kvs.append(kv_out)
+        return self.ln(x), new_kvs
+
+class ARHead(nn.Module):
+    def __init__(self, d):
+        super().__init__()
+        self.proj = nn.Linear(d, VOCAB)
+    def forward(self, h): return self.proj(h)
+
+# ───────────────────────── Masks ─────────────────────────
+def causal_mask(n):
+    m = torch.full((1, 1, n, n), float("-inf"), device=DEV)
+    return torch.triu(m, 1)
+
+# ───────────────────────── Checkpoint helpers ─────────────────────────
+def save_ckpt(path: pathlib.Path, core: nn.Module, ar_h: nn.Module,
+              opt: torch.optim.Optimizer, scaler: GradScaler, meta: Dict[str, Any]):
+    path.parent.mkdir(exist_ok=True, parents=True)
+    tmp = path.with_suffix(path.suffix + ".tmp")
+    state = {
+        "core": core.state_dict(),
+        "ar": ar_h.state_dict(),
+        "opt": opt.state_dict(),
+        "scaler": scaler.state_dict(),
+        "cfg": meta.get("cfg"),
+        "tokenizer_id": TOKENIZER_ID,
+        **{k: v for k, v in meta.items() if k not in {"cfg"}},
+    }
+    torch.save(state, tmp, _use_new_zipfile_serialization=False)
+    tmp.replace(path)
+    (path.parent / "latest.json").write_text(json.dumps({"path": str(path), "step": meta["step"]}))
+    print(f"\n✓ saved checkpoint {path.name}")
+
+def load_ckpt(path: pathlib.Path, core: nn.Module, ar_h: nn.Module,
+              opt: torch.optim.Optimizer, scaler: GradScaler):
+    p = _resolve_ckpt(path) or path
+    ck = _try_load(p, map_location="cpu")
+    if ck is None:
+        raise FileNotFoundError(f"No valid checkpoint at {p}")
+    core.load_state_dict(ck["core"])
+    if "ar" in ck:
+        ar_h.load_state_dict(ck["ar"])
+    opt.load_state_dict(ck["opt"])
+    scaler.load_state_dict(ck["scaler"])
+    return ck.get("step", 0), ck.get("seen_tok", 0), ck.get("wall_time", time.time())
+
+def _safe_load_any(path: pathlib.Path, tgt: nn.Module, key: str | None = None, rename: str | None = None):
+    p = _resolve_ckpt(path) or path
+    if not p or not p.exists(): return 0
+    ck = _try_load(p, map_location="cpu")
+    if ck is None: return 0
+    sd = ck.get(key, ck) if key else ck
+    if isinstance(sd, dict) and "state_dict" in sd:
+        sd = sd["state_dict"]
+    if rename:
+        sd = {k.replace(rename, "proj."): v for k, v in sd.items() if rename in k}
+    tgt_sd = tgt.state_dict()
+    filt = {k: v for k, v in sd.items() if k in tgt_sd and v.shape == tgt_sd[k].shape}
+    if filt:
+        tgt.load_state_dict(filt, strict=False)
+    return len(filt)
+
+def infer_cfg_from_ckpt(path: pathlib.Path):
+    p = _resolve_ckpt(path) or path
+    if not p.exists(): return None
+    sd = _try_load(p, map_location="cpu")
+    if sd is None: return None
+    if isinstance(sd, dict) and "cfg" in sd and isinstance(sd["cfg"], dict):
+        return dict(sd["cfg"])
+    core = sd.get("core")
+    if core is None: return None
+    emb_w = core.get("emb.weight")
+    if emb_w is None: return None
+    d = emb_w.shape[1]
+    layer_ids = []
+    for k in core.keys():
+        if k.startswith("blocks."):
+            parts = k.split(".")
+            if len(parts) > 2 and parts[1].isdigit():
+                layer_ids.append(int(parts[1]))
+    layers = (max(layer_ids) + 1) if layer_ids else None
+    U = core.get("blocks.0.mha.U")
+    heads = rank = None
+    if U is not None:
+        dk, r = U.shape
+        rank = r
+        heads = d // dk if dk > 0 else None
+    out = {"d": d}
+    if layers is not None: out["layers"] = layers
+    if heads is not None:  out["heads"] = heads
+    if rank is not None:   out["rank"] = rank
+    return out
+
+# ───────────────────────── Train loop helpers ─────────────────────────
+def _parse_grow_plan(s: str) -> List[int]:
+    steps = []
+    for part in s.split(","):
+        part = part.strip()
+        if part:
+            v = int(part)
+            if v >= 128:
+                steps.append(v)
+    return sorted(set(steps))
+
+def _init_save_timers(resume_wall_time: float | None, interval_sec: int) -> Tuple[float, float]:
+    now_wall = time.time()
+    now_mono = time.monotonic()
+    if resume_wall_time is None:
+        return now_wall, now_mono
+    elapsed_wall = max(0.0, now_wall - resume_wall_time)
+    elapsed_clamped = min(float(interval_sec), elapsed_wall)
+    return now_wall, now_mono - elapsed_clamped
+
+def _count_enabled_params(*modules: Optional[nn.Module]) -> int:
+    total = 0
+    for m in modules:
+        if m is not None:
+            total += sum(p.numel() for p in m.parameters())
+    return total
+
+def _make_optimizer(core, ar_h, lr_core: float, lr_head: float):
+    return torch.optim.AdamW([
+        {"params": [p for p in core.parameters() if p.requires_grad], "lr": lr_core},
+        {"params": ar_h.parameters(), "lr": lr_head},
+    ])
+
+def _phase_freeze(core: nn.Module, *, freeze_core: bool, unfreeze_ln: bool, train_emb: bool):
+    for p in core.parameters():
+        p.requires_grad = not freeze_core
+    if freeze_core:
+        if unfreeze_ln:
+            for blk in core.blocks:
+                for p in blk.ln1.parameters(): p.requires_grad = True
+                for p in blk.ln2.parameters(): p.requires_grad = True
+            for p in core.ln.parameters(): p.requires_grad = True
+        if train_emb:
+            for p in core.emb.parameters(): p.requires_grad = True
+
+def _train_phase(
+    args,
+    *,
+    core: nn.Module,
+    ar_h: nn.Module,
+    opt: torch.optim.Optimizer,
+    scaler: GradScaler,
+    start_step: int,
+    seen_tok: int,
+    resume_wall_time: Optional[float],
+    ce_tok,
+    cfg: Dict[str,int],
+    source: str,
+    steps: Optional[int],
+    block: int,
+    save_dir: str,
+    save_every_sec: int,
+    save_every_steps: int,
+    auto_grow: bool,
+    grow_plan_s: str,
+    grow_every_steps: int,
+    chat: bool,
+    chat_messages_key: str,
+    dataset_field_text: str,
+    sft_add_generation_prompt: bool,
+    amp_flag: bool,
+    fp8_only_flag: bool,
+    fp8_fallback_flag: bool,
+    target_tokens_override: Optional[int] = None,
+    phase_name: str = "phase"
+):
+    BLOCK = block
+    pbar = None
+
+    if target_tokens_override is not None:
+        target_tokens = target_tokens_override
+    else:
+        enabled_param_count = _count_enabled_params(core, ar_h)
+        target_tokens = int(25 * enabled_param_count)
+
+    new_tokens_needed = target_tokens - seen_tok
+    if steps:
+        new_tokens_needed = steps * BLOCK
+
+    total_tokens_needed = seen_tok + max(0, new_tokens_needed)
+    if new_tokens_needed <= 0:
+        print(f"[{phase_name}] target already reached – skipping.")
+        return start_step, seen_tok, resume_wall_time
+
+    print(f"[{phase_name}] [auto-steps] {new_tokens_needed // BLOCK:,} steps (@ {BLOCK} tokens/step)")
+    grow_plan = _parse_grow_plan(grow_plan_s) if auto_grow else []
+
+    stream = token_stream(args, target_tokens, seed=42,
+                          source=source, chat=chat, chat_messages_key=chat_messages_key,
+                          sft_add_generation_prompt=sft_add_generation_prompt, dataset_field_text=dataset_field_text)
+    buf: list[int] = []
+    if pbar is None:
+        pbar = tqdm(total=total_tokens_needed, initial=seen_tok, unit="tok")
+
+    last_save_wall, last_save_mono = _init_save_timers(resume_wall_time, save_every_sec)
+    step = start_step; steps_since_last_grow = 0
+
+    while seen_tok < total_tokens_needed:
+        try:
+            while len(buf) < BLOCK:
+                buf.append(next(stream))
+        except StopIteration:
+            break
+        ids = torch.tensor(buf[:BLOCK], device=DEV).unsqueeze(0)
+        buf = buf[BLOCK:]
+        tgt_ar = ids.clone()
+
+        try:
+            with amp(amp_flag or fp8_only_flag, prefer_fp8=fp8_only_flag and (_supports_fp8() or fp8_fallback_flag)):
+                h_ar = core(ids, causal_mask(ids.size(1)))
+                logits_ar = ar_h(h_ar)[:, :-1]
+                loss = ce_tok(logits_ar.reshape(-1, VOCAB), tgt_ar[:, 1:].reshape(-1))
+            scaler.scale(loss).backward()
+            scaler.unscale_(opt)
+            nn.utils.clip_grad_norm_(core.parameters(), 1.0)
+            scaler.step(opt); scaler.update()
+            opt.zero_grad(set_to_none=True)
+        except RuntimeError as e:
+            msg = str(e).lower()
+            if "out of memory" in msg or "cuda error" in msg:
+                new_block = max(128, BLOCK // 2)
+                if new_block < BLOCK:
+                    print(f"\n[{phase_name}][OOM] reducing block from {BLOCK} -> {new_block}")
+                    BLOCK = new_block
+                    if DEV.type == "cuda":
+                        torch.cuda.empty_cache()
+                    buf = ids[0].tolist() + buf
+                    steps_since_last_grow = 0
+                    continue
+            raise
+
+        step += 1; seen_tok += BLOCK
+        pbar.update(BLOCK)
+        pbar.set_postfix_str(f"{phase_name} loss={loss.item():.3f} block={BLOCK}")
+
+        if save_every_sec > 0:
+            now_mono = time.monotonic()
+            if now_mono - last_save_mono >= save_every_sec:
+                ck_name = f"{phase_name}_step{step:08d}.pt"
+                save_ckpt(pathlib.Path(save_dir) / ck_name, core, ar_h, opt, scaler,
+                          meta={"cfg": cfg, "step": step, "seen_tok": seen_tok, "wall_time": time.time(),
+                                "py_state": random.getstate(), "torch_state": rng_state(), "fp8_only": fp8_only_flag})
+                last_save_mono = now_mono
+
+        if save_every_steps > 0 and step > 0 and (step % save_every_steps == 0):
+            ck_name = f"{phase_name}_step{step:08d}.pt"
+            save_ckpt(pathlib.Path(save_dir) / ck_name, core, ar_h, opt, scaler,
+                      meta={"cfg": cfg, "step": step, "seen_tok": seen_tok, "wall_time": time.time(),
+                            "py_state": random.getstate(), "torch_state": rng_state(), "fp8_only": fp8_only_flag})
+
+        if auto_grow:
+            steps_since_last_grow += 1
+            if steps_since_last_grow >= grow_every_steps:
+                steps_since_last_grow = 0
+                try:
+                    idx = grow_plan.index(BLOCK)
+                    if idx + 1 < len(grow_plan):
+                        candidate = grow_plan[idx + 1]
+                        print(f"[{phase_name}][auto-grow] {BLOCK} -> {candidate}")
+                        BLOCK = candidate
+                        if DEV.type == "cuda":
+                            torch.cuda.empty_cache()
+                    else:
+                        print(f"[{phase_name}][auto-grow] at max planned block.")
+                except ValueError:
+                    grow_plan = sorted(set(grow_plan + [BLOCK]))
+                    idx = grow_plan.index(BLOCK)
+                    if idx + 1 < len(grow_plan):
+                        candidate = grow_plan[idx + 1]
+                        print(f"[{phase_name}][auto-grow] moving to planned BLOCK {candidate}")
+                        BLOCK = candidate
+                        if DEV.type == "cuda":
+                            torch.cuda.empty_cache()
+
+    if pbar is not None:
+        pbar.close()
+
+    save_ckpt(pathlib.Path(save_dir) / f"{phase_name}_final.pt", core, ar_h, opt, scaler,
+              meta={"cfg": cfg, "step": step, "seen_tok": seen_tok, "wall_time": time.time(),
+                    "py_state": random.getstate(), "torch_state": rng_state(), "fp8_only": args.fp8_only})
+    print(f"🎉 {phase_name} complete")
+    return step, seen_tok, time.time()
+
+# ───────────────────────── Top-level Train orchestrator ─────────────────────────
+def train(args):
+    cfg = PRESETS[args.preset].copy()
+
+    # probe unless --fresh
+    if not args.fresh:
+        src_probe = pathlib.Path(args.warmstart_from) if args.warmstart_from else pathlib.Path(args.save_dir) / "final.pt"
+        prev_cfg = infer_cfg_from_ckpt(src_probe)
+    else:
+        prev_cfg = None
+
+    if prev_cfg and not args.fresh:
+        cfg["d"] = prev_cfg.get("d", cfg["d"])
+        if prev_cfg.get("heads"): cfg["heads"] = prev_cfg["heads"]
+        if args.rank is None and prev_cfg.get("rank"): cfg["rank"] = prev_cfg["rank"]
+        if prev_cfg.get("layers"): cfg["layers"] = prev_cfg["layers"]
+        if args.x2 and prev_cfg.get("layers"): cfg["layers"] = max(cfg["layers"], prev_cfg["layers"] * 2)
+    if args.rank: cfg["rank"] = args.rank
+    if args.x2 and not prev_cfg: cfg["layers"] *= 2
+
+    BLOCK = args.block or DEFAULT_BLOCK
+
+    core = Encoder(cfg).to(DEV)
+    ar_h = ARHead(cfg["d"]).to(DEV)
+
+    # shape-safe warm-start even in --fresh
+    loaded = 0; src = None
+    if args.warmstart_from:
+        src = _resolve_ckpt(pathlib.Path(args.warmstart_from)) or pathlib.Path(args.warmstart_from)
+    else:
+        maybe = _resolve_ckpt(pathlib.Path(args.save_dir) / "final.pt")
+        if maybe and not args.fresh:
+            src = maybe
+    if src:
+        loaded += _safe_load_any(src, core, key="core")
+        loaded += _safe_load_any(src, ar_h,   key="ar")
+        if loaded:
+            print(f"Warm-start: loaded {loaded} matching tensors from {src}")
+
+    _phase_freeze(core, freeze_core=args.freeze_core, unfreeze_ln=args.unfreeze_ln, train_emb=args.train_emb)
+    opt = _make_optimizer(core, ar_h, args.lr_core, args.lr_head)
+    scaler = GradScaler(enabled=((args.amp or args.fp8_only) and DEV.type == "cuda"))
+    ce_tok = nn.CrossEntropyLoss(label_smoothing=0.1)
+
+    start_step, seen_tok = 0, 0
+    last_save_wall = None
+    if args.resume and not args.fresh:
+        start_step, seen_tok, last_save_wall = load_ckpt(pathlib.Path(args.resume), core, ar_h, opt, scaler)
+        print(f"✓ resumed from step {start_step:,}, seen_tokens={seen_tok:,}")
+
+    # Phase A: pretrain
+    step, seen_tok, last_save_wall = _train_phase(
+        args,
+        core=core, ar_h=ar_h, opt=opt, scaler=scaler,
+        start_step=start_step, seen_tok=seen_tok, resume_wall_time=last_save_wall,
+        ce_tok=ce_tok, cfg=cfg,
+        source=args.source, steps=args.steps, block=BLOCK,
+        save_dir=args.save_dir, save_every_sec=args.save_every_sec, save_every_steps=args.save_every_steps,
+        auto_grow=args.auto_grow, grow_plan_s=args.grow_plan, grow_every_steps=args.grow_every_steps,
+        chat=args.chat, chat_messages_key=args.chat_messages_key, dataset_field_text=args.dataset_field_text,
+        sft_add_generation_prompt=args.sft_add_generation_prompt,
+        amp_flag=args.amp, fp8_only_flag=args.fp8_only, fp8_fallback_flag=args.fp8_fallback,
+        target_tokens_override=(args.target_tokens if args.target_tokens else None),
+        phase_name="pretrain"
+    )
+
+    # Auto-wire Phase B defaults if steps provided but no source
+    if (not args.after_sft_source) and (args.after_sft_steps and args.after_sft_steps > 0):
+        args.after_sft_source = DEFAULT_AFTER_SFT_SOURCES
+        args.after_sft_chat = True
+        if args.after_sft_add_generation_prompt is None:
+            args.after_sft_add_generation_prompt = True
+        if not args.after_sft_block or args.after_sft_block <= 0:
+            args.after_sft_block = DEFAULT_AFTER_SFT_BLOCK
+
+    if args.after_sft_source and args.after_sft_steps and args.after_sft_steps > 0:
+        print("\n[after-sft] starting automatic post-pretraining chat SFT phase")
+        _phase_freeze(core,
+                      freeze_core=args.after_sft_freeze_core,
+                      unfreeze_ln=args.after_sft_unfreeze_ln,
+                      train_emb=args.after_sft_train_emb)
+        opt = _make_optimizer(core, ar_h,
+                              args.after_sft_lr_core or args.lr_core,
+                              args.after_sft_lr_head or args.lr_head)
+
+        step, seen_tok, last_save_wall = _train_phase(
+            args,
+            core=core, ar_h=ar_h, opt=opt, scaler=scaler,
+            start_step=step, seen_tok=seen_tok, resume_wall_time=last_save_wall,
+            ce_tok=ce_tok, cfg=cfg,
+            source=args.after_sft_source, steps=args.after_sft_steps,
+            block=args.after_sft_block or DEFAULT_AFTER_SFT_BLOCK,
+            save_dir=args.save_dir, save_every_sec=args.save_every_sec, save_every_steps=args.save_every_steps,
+            auto_grow=args.after_sft_auto_grow, grow_plan_s=(args.after_sft_grow_plan or args.grow_plan),
+            grow_every_steps=(args.after_sft_grow_every_steps or args.grow_every_steps),
+            chat=args.after_sft_chat, chat_messages_key=args.after_sft_chat_messages_key,
+            dataset_field_text=args.after_sft_dataset_field_text,
+            sft_add_generation_prompt=(args.after_sft_add_generation_prompt
+                                       if args.after_sft_add_generation_prompt is not None
+                                       else args.sft_add_generation_prompt),
+            amp_flag=args.amp, fp8_only_flag=args.fp8_only, fp8_fallback_flag=args.fp8_fallback,
+            target_tokens_override=None,
+            phase_name="sft"
+        )
+
+    save_ckpt(pathlib.Path(args.save_dir) / "final.pt", core, ar_h, opt, scaler,
+              meta={"cfg": cfg, "step": step, "seen_tok": seen_tok, "wall_time": time.time(),
+                    "py_state": random.getstate(), "torch_state": rng_state(), "fp8_only": args.fp8_only})
+    print("🎉 training complete")
+
+# ───────────────────────── Sampling utils ─────────────────────────
+def _apply_no_repeat_ngram(logits: torch.Tensor, ids: torch.Tensor, n: int):
+    if n <= 0 or ids.size(1) < n - 1:
+        return logits
+    prefix = ids[0, - (n - 1):].tolist()
+    banned = []
+    tokens = ids[0].tolist()
+    for i in range(len(tokens) - n + 1):
+        if tokens[i:i + n - 1] == prefix:
+            banned.append(tokens[i + n - 1])
+    if banned:
+        banned_idx = torch.tensor(banned, device=logits.device, dtype=torch.long)
+        logits[..., banned_idx] = float("-inf")
+    return logits
+
+def _apply_rep_presence_frequency(
+    logits: torch.Tensor, ids: torch.Tensor, last_n: int,
+    repetition_penalty: float, presence_penalty: float, frequency_penalty: float
+):
+    if ids.numel() == 0:
+        return logits
+    hist = ids[0, -last_n:].to(torch.long) if last_n > 0 else ids[0].to(torch.long)
+    if hist.numel() == 0:
+        return logits
+    uniq, counts = torch.unique(hist, return_counts=True)
+    if presence_penalty != 0.0 or frequency_penalty != 0.0:
+        adjust = presence_penalty + frequency_penalty * counts.to(logits.dtype)
+        logits[..., uniq] = logits[..., uniq] - adjust
+    if repetition_penalty and abs(repetition_penalty - 1.0) > 1e-6:
+        sel = logits[..., uniq]
+        sel = torch.where(sel > 0, sel / repetition_penalty, sel * repetition_penalty)
+        logits[..., uniq] = sel
+    return logits
+
+def _filter_top_k_top_p_min_p(
+    logits: torch.Tensor, top_k: int, top_p: float, min_p: float, temperature: float
+) -> torch.Tensor:
+    logits = logits / max(temperature, 1e-8)
+    if logits.dim() == 1:
+        logits = logits.unsqueeze(0)
+    probs = logits.softmax(-1)
+    if torch.isnan(probs).any() or torch.isinf(probs).any():
+        probs = torch.nan_to_num(probs, nan=0.0, posinf=0.0, neginf=0.0)
+    V = probs.size(-1)
+    if top_k and top_k < V:
+        vals, idx = torch.topk(probs, top_k, dim=-1)
+        mask = torch.full_like(probs, 0.0)
+        mask.scatter_((1 if probs.dim() == 2 else -1), idx, 1.0)
+        probs = probs * mask
+    if top_p < 1.0:
+        sorted_probs, sorted_idx = torch.sort(probs, descending=True, dim=-1)
+        cumsum = torch.cumsum(sorted_probs, dim=-1)
+        keep = cumsum <= top_p
+        keep[..., 0] = True
+        mask = torch.zeros_like(probs)
+        mask.scatter_(1, sorted_idx, keep.to(mask.dtype))
+        probs = probs * mask
+    if min_p > 0.0:
+        probs = torch.where(probs >= min_p, probs, torch.zeros_like(probs))
+    sums = probs.sum(-1, keepdim=True)
+    empty = (sums == 0)
+    if empty.any():
+        fallback_idx = logits.argmax(-1, keepdim=True)
+        probs = torch.where(empty, torch.zeros_like(probs), probs)
+        probs.scatter_(-1, fallback_idx, torch.where(empty, torch.ones_like(sums), torch.zeros_like(sums)))
+    probs = probs / probs.sum(-1, keepdim=True)
+    return probs
+
+# ───────────────────────── Inference helpers ─────────────────────────
+def load_joint(ckpt: str, preset: str):
+    path = _resolve_ckpt(pathlib.Path(ckpt)) or pathlib.Path(ckpt)
+    sd = _try_load(path, map_location="cpu")
+    if sd is None:
+        raise FileNotFoundError(f"No valid checkpoint at {path}")
+    cfg = sd["cfg"] if "cfg" in sd and isinstance(sd["cfg"], dict) else (infer_cfg_from_ckpt(path) or PRESETS[preset])
+    core = Encoder(cfg).to(DEV)
+    ar_h = ARHead(cfg["d"]).to(DEV)
+    core.load_state_dict(sd["core"])
+    if "ar" in sd:
+        ar_h.load_state_dict(sd["ar"])
+    return core, ar_h
+
+def _warn_tokenizer_mismatch(sd_tokenizer_id: str | None):
+    if not sd_tokenizer_id:
+        return
+    if sd_tokenizer_id != TOKENIZER_ID:
+        print(f"[warn] tokenizer mismatch: ckpt used '{sd_tokenizer_id}', runtime is '{TOKENIZER_ID}'. Expect degraded outputs.", file=sys.stderr)
+
+DECODE_PRESETS = {
+    "det": dict(greedy=True, temperature=1.0, top_k=0, top_p=1.0, min_p=0.0,
+                repetition_penalty=1.05, presence_penalty=0.0, frequency_penalty=0.0,
+                penalty_last_n=128, no_repeat_ngram_size=3),
+    "balanced": dict(greedy=False, temperature=0.7, top_k=40, top_p=0.9, min_p=0.0,
+                     repetition_penalty=1.1, presence_penalty=0.3, frequency_penalty=0.3,
+                     penalty_last_n=256, no_repeat_ngram_size=3),
+    "creative": dict(greedy=False, temperature=0.85, top_k=80, top_p=0.95, min_p=0.0,
+                     repetition_penalty=1.05, presence_penalty=0.2, frequency_penalty=0.2,
+                     penalty_last_n=256, no_repeat_ngram_size=3),
+}
+
+@torch.no_grad()
+def ar_decode(core, ar_h, prompt: str, max_new: int, T: float,
+              greedy: bool, top_k: int, top_p: float, min_p: float,
+              repetition_penalty: float, presence_penalty: float,
+              frequency_penalty: float, penalty_last_n: int,
+              no_repeat_ngram_size: int,
+              use_fp8: bool, fp8_fallback: bool):
+    prompt_ids = tok.encode(prompt)
+    if len(prompt_ids) == 0:
+        ids = torch.tensor([[EOS] if EOS is not None else [0]], device=DEV); prompt_len = 0
+    else:
+        ids = torch.tensor([prompt_ids], device=DEV); prompt_len = ids.size(1)
+
+    t0 = time.time()
+    with amp(use_fp8 or False, prefer_fp8=use_fp8 and (_supports_fp8() or fp8_fallback)):
+        h_full, kvs = core(ids, causal_mask(ids.size(1)), use_cache=True)
+        for _ in range(max_new):
+            logits = ar_h(h_full)[:, -1]
+            logits = _apply_no_repeat_ngram(logits, ids, no_repeat_ngram_size)
+            logits = _apply_rep_presence_frequency(logits, ids, penalty_last_n,
+                                                   repetition_penalty, presence_penalty, frequency_penalty)
+            if greedy:
+                nxt = logits.argmax(-1, keepdim=True)
+            else:
+                probs = _filter_top_k_top_p_min_p(logits.squeeze(0), top_k, top_p, min_p, T)
+                nxt = probs.multinomial(1)
+            ids = torch.cat([ids, nxt.unsqueeze(0) if nxt.dim()==1 else nxt], 1)
+            x = ids[:, -1:]; h_full, kvs = core(x, None, kv_caches=kvs, use_cache=True)
+
+    full_ids = ids[0].tolist()
+    prompt_text = tok.decode(full_ids[:prompt_len], skip_special_tokens=True)
+    gen_text    = tok.decode(full_ids[prompt_len:], skip_special_tokens=True)
+
+    if sys.stdout.isatty():
+        sys.stdout.write("\x1b[90m"); sys.stdout.write(prompt_text); sys.stdout.write("\x1b[0m"); sys.stdout.write(gen_text + "\n")
+    else:
+        sys.stdout.write(prompt_text + gen_text + "\n")
+
+    print(f"[{len(full_ids) - prompt_len} tok in {time.time() - t0:.2f}s]")
+
+# ───────────────────────── CLI ─────────────────────────
+def main():
+    ap = argparse.ArgumentParser()
+    sub = ap.add_subparsers(dest="cmd", required=True)
+
+    tr = sub.add_parser("train")
+    tr.add_argument("--preset", choices=PRESETS, default="base17")
+    tr.add_argument("--rank", type=int)
+    tr.add_argument("--block", type=int, default=DEFAULT_BLOCK)
+    tr.add_argument("--source", default=DEFAULT_PRETRAIN_SOURCES,
+                    help="Comma-separated datasets (optionally dataset:config), or json:/path.jsonl")
+    tr.add_argument("--target_tokens", type=int)
+    tr.add_argument("--steps", type=int)
+    tr.add_argument("--amp", action="store_true")
+    tr.add_argument("--save_every_sec", type=int, default=DEFAULT_SAVE_SEC)
+    tr.add_argument("--save_every_steps", type=int, default=0)
+    tr.add_argument("--save_dir", default=str(CKDIR))
+    tr.add_argument("--resume", type=str)
+    tr.add_argument("--x2", action="store_true")
+    tr.add_argument("--warmstart_from", type=str, default=None)
+    tr.add_argument("--fresh", action="store_true")
+
+    # FP8 control
+    tr.add_argument("--fp8-only", action="store_true", dest="fp8_only")
+    tr.add_argument("--fp8-fallback", action="store_true", dest="fp8_fallback")
+
+    # Progressive block growth
+    tr.add_argument("--auto_grow", action="store_true")
+    tr.add_argument("--grow_plan", type=str, default="576,768,1024")
+    tr.add_argument("--grow_every_steps", type=int, default=50000)
+
+    # Chat / dataset fields
+    tr.add_argument("--chat", action="store_true")
+    tr.add_argument("--chat_messages_key", type=str, default="messages")
+    tr.add_argument("--dataset_field_text", type=str, default="text")
+    tr.add_argument("--sft_add_generation_prompt", action="store_true")
+
+    # Phase A freezing / LRs
+    tr.add_argument("--freeze_core", action="store_true")
+    tr.add_argument("--unfreeze_ln", action="store_true")
+    tr.add_argument("--train_emb", action="store_true")
+    tr.add_argument("--lr_core", type=float, default=LR_CORE)
+    tr.add_argument("--lr_head", type=float, default=LR_HEAD)
+
+    # Phase B: automatic SFT
+    tr.add_argument("--after_sft_source", type=str, default="")
+    tr.add_argument("--after_sft_steps", type=int, default=0)
+    tr.add_argument("--after_sft_chat", action="store_true")
+    tr.add_argument("--after_sft_chat_messages_key", type=str, default="messages")
+    tr.add_argument("--after_sft_dataset_field_text", type=str, default="text")
+    tr.add_argument("--after_sft_add_generation_prompt", type=lambda x: str(x).lower() in {"1","true","yes"}, default=None)
+    tr.add_argument("--after_sft_block", type=int, default=0)
+    tr.add_argument("--after_sft_auto_grow", action="store_true")
+    tr.add_argument("--after_sft_grow_plan", type=str, default="")
+    tr.add_argument("--after_sft_grow_every_steps", type=int, default=0)
+    tr.add_argument("--after_sft_freeze_core", action="store_true")
+    tr.add_argument("--after_sft_unfreeze_ln", action="store_true")
+    tr.add_argument("--after_sft_train_emb", action="store_true")
+    tr.add_argument("--after_sft_lr_core", type=float, default=0.0)
+    tr.add_argument("--after_sft_lr_head", type=float, default=0.0)
+
+    inf = sub.add_parser("infer")
+    inf.add_argument("--mode", choices=["ar"], required=True)
+    inf.add_argument("--ckpt", required=True)
+    inf.add_argument("--preset", default="base17")
+    inf.add_argument("--prompt", required=True)
+    inf.add_argument("--max_new", type=int, default=256)
+    inf.add_argument("--seed", type=int, default=1234)
+    inf.add_argument("--greedy", action="store_true")
+    inf.add_argument("--temperature", type=float, default=0.7)
+    inf.add_argument("--top_k", type=int, default=40)
+    inf.add_argument("--top_p", type=float, default=0.9)
+    inf.add_argument("--min_p", type=float, default=0.0)
+    inf.add_argument("--repetition_penalty", type=float, default=1.1)
+    inf.add_argument("--presence_penalty", type=float, default=0.3)
+    inf.add_argument("--frequency_penalty", type=float, default=0.3)
+    inf.add_argument("--penalty_last_n", type=int, default=256)
+    inf.add_argument("--no_repeat_ngram_size", type=int, default=3)
+    inf.add_argument("--fp8-only", action="store_true", dest="fp8_only")
+    inf.add_argument("--fp8-fallback", action="store_true", default=False, dest="fp8_fallback")
+    inf.add_argument("--decode_preset", choices=["det","balanced","creative"], default="balanced")
+
+    args = ap.parse_args()
+    if args.cmd == "train":
+        if args.fp8_only:
+            print("[init] FP8-only requested. If FP8 kernels are missing, use --fp8-fallback to continue with bf16.")
+        train(args)
+    else:
+        core, ar_h = load_joint(args.ckpt, args.preset)
+        try:
+            p = _resolve_ckpt(pathlib.Path(args.ckpt)) or pathlib.Path(args.ckpt)
+            _sd = _try_load(p, map_location="cpu")
+            _warn_tokenizer_mismatch(_sd.get("tokenizer_id") if isinstance(_sd, dict) else None)
+        except Exception:
+            pass
+        set_seed(args.seed)
+        dp = DECODE_PRESETS.get(args.decode_preset, {})
+        g  = dp.get("greedy", args.greedy)
+        T  = dp.get("temperature", args.temperature)
+        k  = dp.get("top_k", args.top_k)
+        p_ = dp.get("top_p", args.top_p)
+        mp = dp.get("min_p", args.min_p)
+        rp = dp.get("repetition_penalty", args.repetition_penalty)
+        pp = dp.get("presence_penalty", args.presence_penalty)
+        fp = dp.get("frequency_penalty", args.frequency_penalty)
+        ln = dp.get("penalty_last_n", args.penalty_last_n)
+        ng = dp.get("no_repeat_ngram_size", args.no_repeat_ngram_size)
+
+        ar_decode(core, ar_h, args.prompt, args.max_new, T,
+                  g, k, p_, mp, rp, pp, fp, ln, ng,
+                  use_fp8=args.fp8_only, fp8_fallback=args.fp8_fallback if hasattr(args, "fp8_fallback") else False)
+
+if __name__ == "__main__":
+    main()