260 lines
9.5 KiB
Python
260 lines
9.5 KiB
Python
# Copyright 2019 The TensorFlow Authors. All Rights Reserved.
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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# ==============================================================================
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"""Python wrapper for post training quantization with calibration."""
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import numpy as np
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from tensorflow.lite.python.convert_phase import Component
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from tensorflow.lite.python.convert_phase import convert_phase
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from tensorflow.lite.python.convert_phase import SubComponent
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from tensorflow.lite.python.interpreter import Interpreter
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from tensorflow.python.framework import dtypes
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from tensorflow.python.util.lazy_loader import LazyLoader
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# Lazy load since some of the performance benchmark skylark rules
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# break dependencies. Must use double quotes to match code internal rewrite
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# rule.
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_calibration_wrapper = LazyLoader(
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"_calibration_wrapper",
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globals(),
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(
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"tensorflow.lite.python.optimize."
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"_pywrap_tensorflow_lite_calibration_wrapper"
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),
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)
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def add_intermediate_tensors(model_content):
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"""Adds intermediate tensors to fused op if needed."""
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return _calibration_wrapper.AddIntermediateTensors(model_content)
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class Calibrator:
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"""Calibrates a floating point model and then quantizes it.
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This is an internal class, not a public interface.
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"""
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def __init__(
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self,
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model_content,
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custom_op_registerers_by_name=None,
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custom_op_registerers_by_func=None,
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):
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"""Constructor.
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Args:
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model_content: Content of a TF-Lite Flatbuffer file.
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custom_op_registerers_by_name: List of str (symbol names) that take a
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pointer to a MutableOpResolver and register custom ops.
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custom_op_registerers_by_func: List of functions that take a pointer to a
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MutableOpResolver and register custom ops.
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Raises:
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ValueError: If the calibrator was unable to open the model.
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"""
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if not model_content:
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raise ValueError("`model_content` must be specified.")
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if custom_op_registerers_by_name is None:
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custom_op_registerers_by_name = []
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if custom_op_registerers_by_func is None:
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custom_op_registerers_by_func = []
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try:
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self._calibrator = _calibration_wrapper.CalibrationWrapper(
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model_content,
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custom_op_registerers_by_name,
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custom_op_registerers_by_func,
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)
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self._model_content = model_content
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except Exception as e:
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raise ValueError("Failed to parse the model: %s." % e)
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if not self._calibrator:
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raise ValueError("Failed to parse the model.")
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self._interpreter = None
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def _create_input_array_from_dict(self, signature_key, inputs):
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input_array = []
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signature_runner = self._interpreter.get_signature_runner(signature_key)
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input_details = sorted(
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signature_runner.get_input_details().items(),
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key=lambda item: item[1]["index"],
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)
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for input_name, _ in input_details:
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input_array.append(inputs[input_name])
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return input_array
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def _feed_tensors(self, dataset_gen, resize_input):
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"""Feed tensors to the calibrator."""
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initialized = {}
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for sample in dataset_gen():
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if isinstance(sample, tuple):
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if not isinstance(sample[1], dict):
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raise ValueError(
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"You need to provide either a dictionary with input "
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"names and values in the second argument in the "
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"tuple"
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)
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# Convert signature based inputs to the tensor index based data.
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if self._interpreter is None:
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self._interpreter = Interpreter(model_content=self._model_content)
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signature_key = sample[0]
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input_array = self._create_input_array_from_dict(
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signature_key, sample[1]
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)
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elif isinstance(sample, dict):
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# Convert signature based inputs to the tensor index based data.
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if self._interpreter is None:
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self._interpreter = Interpreter(model_content=self._model_content)
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signature_key = None
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input_array = self._create_input_array_from_dict(None, sample)
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elif isinstance(sample, list):
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signature_key = None
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input_array = sample
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else:
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raise ValueError(
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"You need to provide either a dictionary with input "
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"names and values, a tuple with signature key and a "
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"dictionary with input names and values, or an array "
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"with input values in the order of input tensors of "
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"the graph in the representative_dataset function. "
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"Unsupported value from dataset: {}.".format(sample)
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)
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if signature_key not in initialized:
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initialized[signature_key] = True
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if resize_input:
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if signature_key is not None:
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self._calibrator.Prepare(
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[list(s.shape) for s in input_array], signature_key
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)
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else:
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self._calibrator.Prepare([list(s.shape) for s in input_array])
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else:
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if signature_key is not None:
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self._calibrator.Prepare(signature_key)
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else:
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self._calibrator.Prepare()
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if signature_key is not None:
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self._calibrator.FeedTensor(input_array, signature_key)
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else:
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self._calibrator.FeedTensor(input_array)
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@convert_phase(
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Component.OPTIMIZE_TFLITE_MODEL,
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SubComponent.QUANTIZE_USING_DEPRECATED_QUANTIZER,
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)
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def calibrate_and_quantize(
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self,
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dataset_gen,
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input_type,
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output_type,
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allow_float,
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activations_type=dtypes.int8,
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bias_type=dtypes.int32,
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resize_input=True,
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disable_per_channel=False,
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disable_per_channel_quantization_for_dense_layers=False,
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):
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"""Calibrates the model with specified generator and then quantizes it.
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The input shapes of the calibrator are resized with the calibration data if
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`resize_input` is set.
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Returns:
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A quantized model.
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Args:
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dataset_gen: A generator that generates calibration samples.
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input_type: A tf.dtype representing the desired real-value input type.
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output_type: A tf.dtype representing the desired real-value output type.
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allow_float: A boolean. False if the resulting model cannot perform float
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computation, useful when targeting an integer-only backend. If False, an
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error will be thrown if an operation cannot be quantized, otherwise the
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model will fallback to float ops.
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activations_type: A tf.dtype representing the desired type for
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activations.
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bias_type: A tf.dtype representing the desired type for bias.
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resize_input: A boolean. True if the shape of the sample data is different
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from the input.
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disable_per_channel: A boolean. True if disabling per-channel
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quantization.
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disable_per_channel_quantization_for_dense_layers: A boolean. True if
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disabling per-channel quantization only in Dense layers.
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"""
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self._feed_tensors(dataset_gen, resize_input)
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return self._calibrator.QuantizeModel(
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np.dtype(input_type.as_numpy_dtype()).num,
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np.dtype(output_type.as_numpy_dtype()).num,
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allow_float,
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np.dtype(activations_type.as_numpy_dtype()).num,
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np.dtype(bias_type.as_numpy_dtype()).num,
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disable_per_channel,
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disable_per_channel_quantization_for_dense_layers,
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)
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@convert_phase(
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Component.OPTIMIZE_TFLITE_MODEL,
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SubComponent.QUANTIZE_USING_DEPRECATED_QUANTIZER,
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)
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def calibrate_and_quantize_single(
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self,
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dataset_gen,
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input_type,
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output_type,
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allow_float,
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op_output_name,
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resize_input=True,
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):
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"""Calibrates the model with specified generator and then quantizes it.
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Only the single op with output op_output_name will be quantized.
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The input shapes of the calibrator are resized with the calibration data.
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Returns:
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A quantized model.
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Args:
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dataset_gen: A generator that generates calibration samples.
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input_type: A tf.dtype representing the desired real-value input type.
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output_type: A tf.dtype representing the desired real-value output type.
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allow_float: A boolean. False if the resulting model cannot perform float
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computation, useful when targeting an integer-only backend. If False, an
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error will be thrown if an operation cannot be quantized, otherwise the
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model will fallback to float ops.
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op_output_name: A string, only this op will be quantized.
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resize_input: A boolean. True if the shape of the sample data is different
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from the input.
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"""
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self._feed_tensors(dataset_gen, resize_input)
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return self._calibrator.QuantizeModel(
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np.dtype(input_type.as_numpy_dtype()).num,
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np.dtype(output_type.as_numpy_dtype()).num,
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allow_float,
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op_output_name,
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)
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@convert_phase(Component.OPTIMIZE_TFLITE_MODEL, SubComponent.CALIBRATE)
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def calibrate(self, dataset_gen):
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"""Calibrates the model with specified generator.
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Returns:
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A model with min and max calibration stats.
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Args:
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dataset_gen: A generator that generates calibration samples.
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"""
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self._feed_tensors(dataset_gen, resize_input=True)
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return self._calibrator.Calibrate()
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