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chore: import upstream snapshot with attribution
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Python

# Copyright 2019 The TensorFlow 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.
# ==============================================================================
"""Python wrapper for post training quantization with calibration."""
import numpy as np
from tensorflow.lite.python.convert_phase import Component
from tensorflow.lite.python.convert_phase import convert_phase
from tensorflow.lite.python.convert_phase import SubComponent
from tensorflow.lite.python.interpreter import Interpreter
from tensorflow.python.framework import dtypes
from tensorflow.python.util.lazy_loader import LazyLoader
# Lazy load since some of the performance benchmark skylark rules
# break dependencies. Must use double quotes to match code internal rewrite
# rule.
_calibration_wrapper = LazyLoader(
"_calibration_wrapper",
globals(),
(
"tensorflow.lite.python.optimize."
"_pywrap_tensorflow_lite_calibration_wrapper"
),
)
def add_intermediate_tensors(model_content):
"""Adds intermediate tensors to fused op if needed."""
return _calibration_wrapper.AddIntermediateTensors(model_content)
class Calibrator:
"""Calibrates a floating point model and then quantizes it.
This is an internal class, not a public interface.
"""
def __init__(
self,
model_content,
custom_op_registerers_by_name=None,
custom_op_registerers_by_func=None,
):
"""Constructor.
Args:
model_content: Content of a TF-Lite Flatbuffer file.
custom_op_registerers_by_name: List of str (symbol names) that take a
pointer to a MutableOpResolver and register custom ops.
custom_op_registerers_by_func: List of functions that take a pointer to a
MutableOpResolver and register custom ops.
Raises:
ValueError: If the calibrator was unable to open the model.
"""
if not model_content:
raise ValueError("`model_content` must be specified.")
if custom_op_registerers_by_name is None:
custom_op_registerers_by_name = []
if custom_op_registerers_by_func is None:
custom_op_registerers_by_func = []
try:
self._calibrator = _calibration_wrapper.CalibrationWrapper(
model_content,
custom_op_registerers_by_name,
custom_op_registerers_by_func,
)
self._model_content = model_content
except Exception as e:
raise ValueError("Failed to parse the model: %s." % e)
if not self._calibrator:
raise ValueError("Failed to parse the model.")
self._interpreter = None
def _create_input_array_from_dict(self, signature_key, inputs):
input_array = []
signature_runner = self._interpreter.get_signature_runner(signature_key)
input_details = sorted(
signature_runner.get_input_details().items(),
key=lambda item: item[1]["index"],
)
for input_name, _ in input_details:
input_array.append(inputs[input_name])
return input_array
def _feed_tensors(self, dataset_gen, resize_input):
"""Feed tensors to the calibrator."""
initialized = {}
for sample in dataset_gen():
if isinstance(sample, tuple):
if not isinstance(sample[1], dict):
raise ValueError(
"You need to provide either a dictionary with input "
"names and values in the second argument in the "
"tuple"
)
# Convert signature based inputs to the tensor index based data.
if self._interpreter is None:
self._interpreter = Interpreter(model_content=self._model_content)
signature_key = sample[0]
input_array = self._create_input_array_from_dict(
signature_key, sample[1]
)
elif isinstance(sample, dict):
# Convert signature based inputs to the tensor index based data.
if self._interpreter is None:
self._interpreter = Interpreter(model_content=self._model_content)
signature_key = None
input_array = self._create_input_array_from_dict(None, sample)
elif isinstance(sample, list):
signature_key = None
input_array = sample
else:
raise ValueError(
"You need to provide either a dictionary with input "
"names and values, a tuple with signature key and a "
"dictionary with input names and values, or an array "
"with input values in the order of input tensors of "
"the graph in the representative_dataset function. "
"Unsupported value from dataset: {}.".format(sample)
)
if signature_key not in initialized:
initialized[signature_key] = True
if resize_input:
if signature_key is not None:
self._calibrator.Prepare(
[list(s.shape) for s in input_array], signature_key
)
else:
self._calibrator.Prepare([list(s.shape) for s in input_array])
else:
if signature_key is not None:
self._calibrator.Prepare(signature_key)
else:
self._calibrator.Prepare()
if signature_key is not None:
self._calibrator.FeedTensor(input_array, signature_key)
else:
self._calibrator.FeedTensor(input_array)
@convert_phase(
Component.OPTIMIZE_TFLITE_MODEL,
SubComponent.QUANTIZE_USING_DEPRECATED_QUANTIZER,
)
def calibrate_and_quantize(
self,
dataset_gen,
input_type,
output_type,
allow_float,
activations_type=dtypes.int8,
bias_type=dtypes.int32,
resize_input=True,
disable_per_channel=False,
disable_per_channel_quantization_for_dense_layers=False,
):
"""Calibrates the model with specified generator and then quantizes it.
The input shapes of the calibrator are resized with the calibration data if
`resize_input` is set.
Returns:
A quantized model.
Args:
dataset_gen: A generator that generates calibration samples.
input_type: A tf.dtype representing the desired real-value input type.
output_type: A tf.dtype representing the desired real-value output type.
allow_float: A boolean. False if the resulting model cannot perform float
computation, useful when targeting an integer-only backend. If False, an
error will be thrown if an operation cannot be quantized, otherwise the
model will fallback to float ops.
activations_type: A tf.dtype representing the desired type for
activations.
bias_type: A tf.dtype representing the desired type for bias.
resize_input: A boolean. True if the shape of the sample data is different
from the input.
disable_per_channel: A boolean. True if disabling per-channel
quantization.
disable_per_channel_quantization_for_dense_layers: A boolean. True if
disabling per-channel quantization only in Dense layers.
"""
self._feed_tensors(dataset_gen, resize_input)
return self._calibrator.QuantizeModel(
np.dtype(input_type.as_numpy_dtype()).num,
np.dtype(output_type.as_numpy_dtype()).num,
allow_float,
np.dtype(activations_type.as_numpy_dtype()).num,
np.dtype(bias_type.as_numpy_dtype()).num,
disable_per_channel,
disable_per_channel_quantization_for_dense_layers,
)
@convert_phase(
Component.OPTIMIZE_TFLITE_MODEL,
SubComponent.QUANTIZE_USING_DEPRECATED_QUANTIZER,
)
def calibrate_and_quantize_single(
self,
dataset_gen,
input_type,
output_type,
allow_float,
op_output_name,
resize_input=True,
):
"""Calibrates the model with specified generator and then quantizes it.
Only the single op with output op_output_name will be quantized.
The input shapes of the calibrator are resized with the calibration data.
Returns:
A quantized model.
Args:
dataset_gen: A generator that generates calibration samples.
input_type: A tf.dtype representing the desired real-value input type.
output_type: A tf.dtype representing the desired real-value output type.
allow_float: A boolean. False if the resulting model cannot perform float
computation, useful when targeting an integer-only backend. If False, an
error will be thrown if an operation cannot be quantized, otherwise the
model will fallback to float ops.
op_output_name: A string, only this op will be quantized.
resize_input: A boolean. True if the shape of the sample data is different
from the input.
"""
self._feed_tensors(dataset_gen, resize_input)
return self._calibrator.QuantizeModel(
np.dtype(input_type.as_numpy_dtype()).num,
np.dtype(output_type.as_numpy_dtype()).num,
allow_float,
op_output_name,
)
@convert_phase(Component.OPTIMIZE_TFLITE_MODEL, SubComponent.CALIBRATE)
def calibrate(self, dataset_gen):
"""Calibrates the model with specified generator.
Returns:
A model with min and max calibration stats.
Args:
dataset_gen: A generator that generates calibration samples.
"""
self._feed_tensors(dataset_gen, resize_input=True)
return self._calibrator.Calibrate()