examples/quantization/utils.py

# Copyright (c) Meta Platforms, Inc. and affiliates.
# All rights reserved.
#
# This source code is licensed under the BSD-style license found in the
# LICENSE file in the root directory of this source tree.

import logging

from torch.ao.quantization.quantize_pt2e import convert_pt2e, prepare_pt2e
from torch.ao.quantization.quantizer.xnnpack_quantizer import (
    get_symmetric_quantization_config,
    XNNPACKQuantizer,
)


def quantize(model, example_inputs):
    """This is the official recommended flow for quantization in pytorch 2.0 export"""
    logging.info(f"Original model: {model}")
    quantizer = XNNPACKQuantizer()
    # if we set is_per_channel to True, we also need to add out_variant of quantize_per_channel/dequantize_per_channel
    operator_config = get_symmetric_quantization_config(is_per_channel=False)
    quantizer.set_global(operator_config)
    m = prepare_pt2e(model, quantizer)
    # calibration
    m(*example_inputs)
    m = convert_pt2e(m)
    logging.info(f"Quantized model: {m}")
    # make sure we can export to flat buffer
    return m