llama.cpp/gguf-py/gguf/quants.py
compilade ee52225067
convert-hf : support direct Q8_0 conversion (#7234)
* convert-hf : support q8_0 conversion

* convert-hf : add missing ftype

This was messing with the checksums otherwise.

* convert-hf : add missing ftype to Baichuan and Xverse

I didn't notice these on my first pass.
2024-05-13 14:10:51 -04:00

110 lines
3.5 KiB
Python

from __future__ import annotations
from typing import Callable
from numpy.typing import DTypeLike
from .constants import GGML_QUANT_SIZES, GGMLQuantizationType
from .lazy import LazyNumpyTensor
import numpy as np
# same as ggml_compute_fp32_to_bf16 in ggml-impl.h
def __compute_fp32_to_bf16(n: np.ndarray) -> np.ndarray:
n = n.astype(np.float32, copy=False).view(np.int32)
# force nan to quiet
n = np.where((n & 0x7fffffff) > 0x7f800000, (n & 0xffff0000) | (64 << 16), n)
# flush subnormals to zero
n = np.where((n & 0x7f800000) == 0, n & 0x80000000, n)
# round to nearest even
n = (n + (0x7fff + ((n >> 16) & 1))) >> 16
return n.astype(np.int16)
# This is faster than np.vectorize and np.apply_along_axis because it works on more than one row at a time
def __apply_over_grouped_rows(func: Callable[[np.ndarray], np.ndarray], arr: np.ndarray, otype: DTypeLike, oshape: tuple[int, ...]) -> np.ndarray:
rows = arr.reshape((-1, arr.shape[-1]))
osize = 1
for dim in oshape:
osize *= dim
out = np.empty(shape=osize, dtype=otype)
# compute over groups of 16 rows (arbitrary, but seems good for performance)
n_groups = rows.shape[0] // 16
np.concatenate([func(group).ravel() for group in np.array_split(rows, n_groups)], axis=0, out=out)
return out.reshape(oshape)
def __quantize_bf16_array(n: np.ndarray) -> np.ndarray:
return __apply_over_grouped_rows(__compute_fp32_to_bf16, arr=n, otype=np.int16, oshape=n.shape)
__quantize_bf16_lazy = LazyNumpyTensor._wrap_fn(__quantize_bf16_array, meta_noop=np.int16)
def quantize_bf16(n: np.ndarray):
if type(n) is LazyNumpyTensor:
return __quantize_bf16_lazy(n)
else:
return __quantize_bf16_array(n)
__q8_block_size, __q8_type_size = GGML_QUANT_SIZES[GGMLQuantizationType.Q8_0]
def can_quantize_to_q8_0(n: np.ndarray) -> bool:
return n.shape[-1] % __q8_block_size == 0
# round away from zero
# ref: https://stackoverflow.com/a/59143326/22827863
def np_roundf(n: np.ndarray) -> np.ndarray:
a = abs(n)
floored = np.floor(a)
b = floored + np.floor(2 * (a - floored))
return np.sign(n) * b
def __quantize_q8_0_shape_change(s: tuple[int, ...]) -> tuple[int, ...]:
return (*s[:-1], s[-1] // __q8_block_size * __q8_type_size)
# Implementation of Q8_0 with bit-exact same results as reference implementation in ggml-quants.c
def __quantize_q8_0_rows(n: np.ndarray) -> np.ndarray:
shape = n.shape
assert shape[-1] % __q8_block_size == 0
n_blocks = n.size // __q8_block_size
blocks = n.reshape((n_blocks, __q8_block_size)).astype(np.float32, copy=False)
d = abs(blocks).max(axis=1, keepdims=True) / 127
with np.errstate(divide="ignore"):
id = np.where(d == 0, 0, 1 / d)
qs = np_roundf(blocks * id)
# (n_blocks, 2)
d = d.astype(np.float16).view(np.uint8)
# (n_blocks, block_size)
qs = qs.astype(np.int8).view(np.uint8)
assert d.shape[1] + qs.shape[1] == __q8_type_size
return np.concatenate([d, qs], axis=1).reshape(__quantize_q8_0_shape_change(shape))
def __quantize_q8_0_array(n: np.ndarray) -> np.ndarray:
return __apply_over_grouped_rows(__quantize_q8_0_rows, arr=n, otype=np.uint8, oshape=__quantize_q8_0_shape_change(n.shape))
__quantize_q8_0_lazy = LazyNumpyTensor._wrap_fn(
__quantize_q8_0_array,
meta_noop=(np.uint8, __quantize_q8_0_shape_change),
)
def quantize_q8_0(data: np.ndarray):
if type(data) is LazyNumpyTensor:
return __quantize_q8_0_lazy(data)
else:
return __quantize_q8_0_array(data)