Files
mlx-lm/mlx_lm/convert.py
T
jaycoolslm 0081085a91 chore: add model-path param flag for convert API for better clarity (#702)
* chore: add model-path param flag for convert API for better clarity

Signed-off-by: Jake Hall <jaycoolslm@gmail.com>

* chore: refactor argparse for multiple string options

Signed-off-by: Jake Hall <jaycoolslm@gmail.com>

* Update mlx_lm/convert.py

* Update README.md

---------

Signed-off-by: Jake Hall <jaycoolslm@gmail.com>
Co-authored-by: Awni Hannun <awni.hannun@gmail.com>
2025-12-31 12:30:38 -08:00

261 lines
7.3 KiB
Python

# Copyright © 2023-2024 Apple Inc.
import argparse
from pathlib import Path
from typing import Callable, Optional, Union
import mlx.core as mx
import mlx.nn as nn
from mlx.utils import tree_map_with_path
from .utils import (
dequantize_model,
load,
quantize_model,
save,
upload_to_hub,
)
def mixed_quant_predicate_builder(
recipe: str, model: nn.Module, group_size: int = 64
) -> Callable[[str, nn.Module, dict], Union[bool, dict]]:
high_bits = 6
if recipe == "mixed_2_6":
low_bits = 2
elif recipe == "mixed_3_4":
low_bits = 3
high_bits = 4
elif recipe == "mixed_3_6":
low_bits = 3
elif recipe == "mixed_4_6":
low_bits = 4
else:
raise ValueError(f"Invalid quant recipe {recipe}")
down_keys = [k for k, _ in model.named_modules() if "down_proj" in k]
if len(down_keys) == 0:
raise ValueError("Model does not have expected keys for mixed quant.")
# Look for the layer index location in the path:
for layer_location, k in enumerate(down_keys[0].split(".")):
if k.isdigit():
break
num_layers = len(model.layers)
def mixed_quant_predicate(
path: str,
module: nn.Module,
) -> Union[bool, dict]:
"""Implements mixed quantization predicates with similar choices to, for example, llama.cpp's Q4_K_M.
Ref: https://github.com/ggerganov/llama.cpp/blob/917786f43d0f29b7c77a0c56767c0fa4df68b1c5/src/llama.cpp#L5265
By Alex Barron: https://gist.github.com/barronalex/84addb8078be21969f1690c1454855f3
"""
index = (
int(path.split(".")[layer_location])
if len(path.split(".")) > layer_location
else 0
)
use_more_bits = (
index < num_layers // 8
or index >= 7 * num_layers // 8
or (index - num_layers // 8) % 3 == 2
)
if (
"v_proj" in path or "v_a_proj" in path or "v_b_proj" in path
) and use_more_bits:
return {"group_size": group_size, "bits": high_bits}
if "down_proj" in path and use_more_bits:
return {"group_size": group_size, "bits": high_bits}
if "lm_head" in path:
return {"group_size": group_size, "bits": high_bits}
return {"group_size": group_size, "bits": low_bits}
return mixed_quant_predicate
QUANT_RECIPES = ["mixed_2_6", "mixed_3_4", "mixed_3_6", "mixed_4_6"]
MODEL_CONVERSION_DTYPES = ["float16", "bfloat16", "float32"]
def convert(
hf_path: str,
mlx_path: str = "mlx_model",
quantize: bool = False,
q_group_size: int = 64,
q_bits: int = 4,
q_mode: str = "affine",
dtype: Optional[str] = None,
upload_repo: str = None,
revision: Optional[str] = None,
dequantize: bool = False,
quant_predicate: Optional[
Union[Callable[[str, nn.Module, dict], Union[bool, dict]], str]
] = None,
trust_remote_code: bool = False,
):
# Check the save path is empty
if isinstance(mlx_path, str):
mlx_path = Path(mlx_path)
if mlx_path.exists():
raise ValueError(
f"Cannot save to the path {mlx_path} as it already exists."
" Please delete the file/directory or specify a new path to save to."
)
print("[INFO] Loading")
model, tokenizer, config = load(
hf_path,
revision=revision,
return_config=True,
tokenizer_config={"trust_remote_code": trust_remote_code},
lazy=True,
)
if isinstance(quant_predicate, str):
quant_predicate = mixed_quant_predicate_builder(
quant_predicate, model, q_group_size
)
if dtype is None:
dtype = config.get("torch_dtype", None)
if dtype in MODEL_CONVERSION_DTYPES:
print("[INFO] Using dtype:", dtype)
dtype = getattr(mx, dtype)
cast_predicate = getattr(model, "cast_predicate", lambda _: True)
def set_dtype(k, v):
if cast_predicate(k) and mx.issubdtype(v.dtype, mx.floating):
return v.astype(dtype)
else:
return v
model.update(tree_map_with_path(set_dtype, model.parameters()))
if quantize and dequantize:
raise ValueError("Choose either quantize or dequantize, not both.")
if quantize:
print("[INFO] Quantizing")
model, config = quantize_model(
model,
config,
q_group_size,
q_bits,
mode=q_mode,
quant_predicate=quant_predicate,
)
if dequantize:
print("[INFO] Dequantizing")
config.pop("quantization", None)
config.pop("quantization_config", None)
model = dequantize_model(model)
save(
mlx_path,
hf_path,
model,
tokenizer,
config,
)
if upload_repo is not None:
upload_to_hub(mlx_path, upload_repo)
def configure_parser() -> argparse.ArgumentParser:
"""
Configures and returns the argument parser for the script.
Returns:
argparse.ArgumentParser: Configured argument parser.
"""
parser = argparse.ArgumentParser(
description="Convert Hugging Face model to MLX format"
)
parser.add_argument(
"--hf-path",
"--model",
type=str,
help="Path to the model. This can be a local path or a Hugging Face Hub model identifier.",
)
parser.add_argument(
"--mlx-path", type=str, default="mlx_model", help="Path to save the MLX model."
)
parser.add_argument(
"-q", "--quantize", help="Generate a quantized model.", action="store_true"
)
parser.add_argument(
"--q-group-size",
help="Group size for quantization.",
type=int,
default=None,
)
parser.add_argument(
"--q-bits",
help="Bits per weight for quantization.",
type=int,
default=None,
)
parser.add_argument(
"--q-mode",
help="The quantization mode.",
type=str,
default="affine",
choices=["affine", "mxfp4", "nvfp4", "mxfp8"],
)
parser.add_argument(
"--quant-predicate",
help=f"Mixed-bit quantization recipe.",
choices=QUANT_RECIPES,
type=str,
required=False,
)
parser.add_argument(
"--dtype",
help="Type to save the non-quantized parameters. Defaults to config.json's `torch_dtype` or the current model weights dtype.",
type=str,
choices=MODEL_CONVERSION_DTYPES,
default=None,
)
parser.add_argument(
"--upload-repo",
help="The Hugging Face repo to upload the model to.",
type=str,
default=None,
)
parser.add_argument(
"-d",
"--dequantize",
help="Dequantize a quantized model.",
action="store_true",
default=False,
)
parser.add_argument(
"--trust-remote-code",
help="Trust remote code when loading tokenizer.",
action="store_true",
default=False,
)
return parser
def main():
parser = configure_parser()
args = parser.parse_args()
convert(**vars(args))
if __name__ == "__main__":
print(
"Calling `python -m mlx_lm.convert ...` directly is deprecated."
" Use `mlx_lm.convert ...` or `python -m mlx_lm convert ...` instead."
)
main()