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paddlepaddle--paddle/python/paddle/quantization/observers/groupwise.py
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2026-07-13 12:40:42 +08:00

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Python

# Copyright (c) 2023 PaddlePaddle Authors. All Rights Reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
import numpy as np
import paddle
from ..base_observer import BaseObserver
from ..factory import ObserverFactory
class GroupWiseWeightObserver(ObserverFactory):
r"""
It collects channel-wise maximum absolute values of target weights.
Args:
bit_length(int, optional): Number of bits to represent an quantized integer in binary.
dtype(str, optional): The data type of input tensor.
name (str, optional): This parameter is used by developers to print debugging information. \
For details, please refer to :ref:`api_guide_Name`. Default is None.
Examples:
.. code-block:: pycon
>>> from paddle.quantization import QuantConfig
>>> from paddle.quantization.quanters import AbsMaxChannelWiseWeightObserver
>>> quanter = AbsMaxChannelWiseWeightObserver()
>>> q_config = QuantConfig(activation=None, weight=quanter)
"""
def __init__(self, quant_bits=8, group_size=128):
super().__init__(quant_bits=quant_bits)
def _get_class(self):
return GroupWiseWeightObserverLayer
class GroupWiseWeightObserverLayer(BaseObserver):
def __init__(self, layer, quant_bits=8, group_size=128):
super().__init__()
self._quant_bits = quant_bits
self.group_size = group_size
self._layer = layer
self._max = None
self._scale = None
self._zero_point = None
def forward(self, inputs):
self._max = self._cal_abs_max(inputs)
return inputs
def _cal_abs_max(self, inputs):
"""Use group_size to group the input, then use the
absmax method to calculate the scale
"""
input_shape = inputs.shape
assert self.group_size == 64 or self.group_size == 128, (
"group_size only support 64 or 128"
)
assert inputs.shape[0] % self.group_size == 0, (
"group_size must be a factor of input channels"
)
assert len(inputs.shape) == 2, "Currently only support 2D tensor"
input_processed = inputs.transpose([1, 0]).reshape(
[input_shape[1], input_shape[0] // self.group_size, self.group_size]
)
abs_max_values = paddle.max(paddle.abs(input_processed), axis=2).cast(
"float32"
)
abs_max_values = paddle.where(
abs_max_values == np.float32(0), np.float32(1e-8), abs_max_values
)
abs_max_values = abs_max_values.transpose([1, 0])
return abs_max_values
def min_value(self) -> float:
return 0.0
def max_value(self) -> float:
return self._max
def bit_length(self):
return self._quant_bits
def quant_axis(self):
return -1
def cal_thresholds(self):
"""Compute thresholds for MAX function."""
if self._scale is None:
self._scale = self._max
self._zero_point = paddle.zeros_like(self._scale)
def scales(self):
"""Return output scales."""
if self._scale is None:
self.cal_thresholds()
return self._scale
def zero_points(self):
"""Return output zero points."""
if self._zero_point is None:
self.cal_thresholds()
return self._zero_point