#!/usr/bin/env python
# ******************************************************************************
# Copyright 2022 Brainchip Holdings Ltd.
#
# 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,
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"""
Common utility methods used in quantization models.
"""
__all__ = ['apply_weights_to_model', 'get_model_input_dtype']
import warnings
import tensorflow as tf
from ..layers import StatefulRecurrent
[docs]def apply_weights_to_model(model, weights, verbose=True):
"""Loads weights from a dictionary and apply it to a model.
Go through the dictionary of weights, find the corresponding variable in the
model and partially load its weights.
Args:
model (keras.Model): the model to update
weights (dict): the dictionary of weights
verbose (bool, optional): if True, throw warning messages if a dict item is not found in the
model. Defaults to True.
"""
if len(weights) == 0:
warnings.warn("There is no weight to apply to the model.")
return
# Go through the dictionary of weights with each item
for key, value in weights.items():
value_applied = False
for dest_var in model.variables:
if key == dest_var.name:
# Apply the current item value
dest_var.assign(value)
value_applied = True
break
if not value_applied and verbose:
warnings.warn(f"Variable '{key}' not found in the model.")
def get_model_input_dtype(model):
"""Retrieve the common input dtype for a model
Handle image like samples (channels in [1, 3]) as uint8, recurrent TENNs as int16 and
other as int8
Args:
model (keras.Model or keras.Sequential): the model to get the input dtype.
Returns:
tf.dtype: the expected input type for the model
"""
if any(isinstance(ly, StatefulRecurrent) for ly in model.layers):
return tf.int16
return tf.uint8 if model.input_shape[-1] in [1, 3] else tf.int8