diff --git a/c/tools/convert_olmoe.py b/c/tools/convert_olmoe.py index dd45806..dc25f6a 100644 --- a/c/tools/convert_olmoe.py +++ b/c/tools/convert_olmoe.py @@ -3,7 +3,10 @@ Downloads or converts a local OLMoE checkpoint (e.g., allenai/OLMoE-1B-7B-0125-Instruct). Dense weights stay as-is (engine reads BF16/F16 → F32 on load). -Expert weights get row-wise int8 quantization with float32 scales. +Expert weights get row-wise symmetric quantization to --ebits bits (default 4) +with float32 scales. Storage stays one value per int8 byte regardless of bits, +matching the engine's expert layout (olmoe.c quantize_rows) — for 4 bits the +values are simply confined to [-8, 7] with scales computed against qmax=7. Usage: python tools/convert_olmoe.py --repo allenai/OLMoE-1B-7B-0125-Instruct --out ./olmoe_i4 @@ -29,12 +32,21 @@ except ImportError as exc: EXPERT_KEY_RE = r"model\.layers\.\d+\.mlp\.experts\.\d+\.(gate_proj|up_proj|down_proj)\.weight" -def quantize_row(w: torch.Tensor) -> tuple[torch.Tensor, torch.Tensor]: - """Row-wise int8 quantization. Returns (int8_weights, float32_scales).""" +def quantize_row(w: torch.Tensor, bits: int = 8) -> tuple[torch.Tensor, torch.Tensor]: + """Row-wise symmetric quantization to `bits` (2..8). + + Returns (int8_weights, float32_scales). Storage is one value per int8 byte + for every bit width — the engine dequantizes as q*scale and never assumes + the full int8 range — mirroring olmoe.c quantize_rows(): + qmax = 2**(bits-1) - 1 (8 -> 127, 4 -> 7, 2 -> 1) + scale = amax(|w|, row) / qmax + q = clamp(round(w / scale), -qmax-1, qmax) + """ + qmax = (1 << (bits - 1)) - 1 w_f32 = w.float() row_max = w_f32.abs().amax(dim=1, keepdim=True).clamp(min=1e-12) - scales = row_max / 127.0 - q = (w_f32 / scales).round().clamp(-128, 127).to(torch.int8) + scales = row_max / qmax + q = (w_f32 / scales).round().clamp(-qmax - 1, qmax).to(torch.int8) return q, scales.squeeze(1) @@ -50,9 +62,12 @@ def main(): src.add_argument("--model", help="Local HF checkpoint directory") ap.add_argument("--out", required=True, help="Output directory for int4 model") ap.add_argument("--ebits", type=int, default=4, - help="Expert quant bits (4 or 8, default 4)") + help="Expert quant bits (2..8, default 4)") args = ap.parse_args() + if not 2 <= args.ebits <= 8: # storage is int8_t; engine rejects the same range (olmoe.c) + sys.exit(f"--ebits must be 2..8 (got {args.ebits})") + if args.repo: from huggingface_hub import snapshot_download from huggingface_hub.errors import LocalEntryNotFoundError @@ -96,7 +111,7 @@ def main(): for name, tensor in tensors.items(): if is_expert_weight(name): expert_count += 1 - q, scales = quantize_row(tensor) + q, scales = quantize_row(tensor, args.ebits) total_expert_f32 += tensor.numel() * tensor.element_size() total_expert_q += q.numel() * 1 + scales.numel() * 4 out_tensors[name] = q @@ -109,7 +124,7 @@ def main(): ratio = total_expert_q / max(total_expert_f32, 1) * 100 print(f"ok") - print(f"\nDone. {expert_count} expert tensors quantized.") + print(f"\nDone. {expert_count} expert tensors quantized to int{args.ebits}.") print(f"Expert storage: {total_expert_f32/1e9:.1f} GB -> {total_expert_q/1e9:.1f} GB ({ratio:.0f}%)") print(f"Model ready at: {out}") print(f"\nRun: SNAP={out} ./olmoe.exe 32 4 16")