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2024-10-30 22:14:35 +01:00

1214 lines
50 KiB
Python

#!/usr/bin/env python
# -------------------------------------------------------------------------
# Copyright (c) Microsoft, Intel Corporation. All rights reserved.
# Licensed under the MIT License. See License.txt in the project root for
# license information.
# --------------------------------------------------------------------------
import abc
import copy
import itertools
import os
import uuid
from enum import Enum
from pathlib import Path
from typing import Dict, Optional, Sequence, Tuple, Union
import numpy as np
import onnx
from onnx import ModelProto, TensorProto, helper, numpy_helper
import onnxruntime
from .quant_utils import apply_plot, load_model_with_shape_infer, smooth_distribution
def rel_entr(pk: np.ndarray, qk: np.ndarray) -> np.ndarray:
"""
See https://docs.scipy.org/doc/scipy/reference/generated/scipy.special.rel_entr.html#scipy.special.rel_entr.
Python implementation.
"""
res = np.empty(pk.shape, dtype=pk.dtype)
res[:] = pk[:] * np.log(pk[:] / qk[:])
c2 = (pk == 0) & (qk >= 0)
res[c2] = 0
c1 = (pk > 0) & (qk > 0)
res[~c1] = np.inf
return res
def entropy(
pk: np.ndarray,
qk: np.ndarray,
base: Optional[float] = None,
axis: int = 0,
) -> np.ndarray:
"""
Simplifeied version of entropy.
Source: https://docs.scipy.org/doc/scipy/reference/generated/scipy.stats.entropy.html.
This avoids taking a dependency on scipy just for this function.
"""
assert base is None or base > 0, "base={base} must be a positive number or `None`."
assert qk is not None, "qk is None"
pk = np.asarray(pk).astype(np.float32)
pk = 1.0 * pk / np.sum(pk, axis=axis, keepdims=True)
qk = np.asarray(qk).astype(np.float32)
pk, qk = np.broadcast_arrays(pk, qk)
qk = 1.0 * qk / np.sum(qk, axis=axis, keepdims=True)
vec = rel_entr(pk, qk)
s = np.sum(vec, axis=axis)
if base is not None:
s /= np.log(base)
return s.astype(pk.dtype)
class TensorData:
_allowed = frozenset(["avg", "std", "lowest", "highest", "hist", "hist_edges", "bins"])
_floats = frozenset(["avg", "std", "lowest", "highest", "hist_edges"])
def __init__(self, **kwargs):
for k, v in kwargs.items():
if k not in TensorData._allowed:
raise ValueError(f"Unexpected value {k!r} not in {TensorData._allowed}.")
if k in TensorData._floats:
if not hasattr(v, "dtype"):
raise ValueError(f"Unexpected type {type(v)} for k={k!r}")
if v.dtype not in (np.float16, np.float32):
raise ValueError(f"Unexpected dtype {v.dtype} for k={k!r}")
setattr(self, k, v)
@property
def range_value(self):
if not hasattr(self, "lowest") or not hasattr(self, "highest"):
raise AttributeError(f"Attributes 'lowest' and/or 'highest' missing in {dir(self)}.")
return (self.lowest, self.highest)
@property
def avg_std(self):
if not hasattr(self, "avg") or not hasattr(self, "std"):
raise AttributeError(f"Attributes 'avg' and/or 'std' missing in {dir(self)}.")
return (self.avg, self.std)
class TensorsData:
def __init__(self, calibration_method, data: Dict[str, Union[TensorData, Tuple]]):
self.calibration_method = calibration_method
self.data = {}
for k, v in data.items():
if not isinstance(k, str):
raise TypeError(f"Keys must be strings not {type(k)}.")
if isinstance(v, tuple):
if calibration_method == CalibrationMethod.MinMax and len(v) == 2:
self.data[k] = TensorData(lowest=v[0], highest=v[1])
continue
if len(v) == 4:
self.data[k] = TensorData(lowest=v[0], highest=v[1], hist=v[2], bins=v[3])
continue
raise TypeError(f"Unexpected tuple for {k:r}, it has {len(v)} elements: {v}.")
if not isinstance(v, TensorData):
raise TypeError(f"Values must be TensorData not {type(v)}.")
self.data[k] = v
def __iter__(self):
yield from self.data
def __contains__(self, key):
return key in self.data
def __getitem__(self, key):
return self.data[key]
def __setitem__(self, key, value):
if key not in self.data:
raise RuntimeError(f"Only an existing tensor can be modified, {key!r} is not.")
self.data[key] = value
def values(self):
return self.data.values()
def items(self):
return self.data.items()
class CalibrationMethod(Enum):
MinMax = 0
Entropy = 1
Percentile = 2
Distribution = 3
class CalibrationDataReader(metaclass=abc.ABCMeta):
@classmethod
def __subclasshook__(cls, subclass):
return hasattr(subclass, "get_next") and callable(subclass.get_next) or NotImplemented
@abc.abstractmethod
def get_next(self) -> dict:
"""generate the input data dict for ONNXinferenceSession run"""
raise NotImplementedError
def __iter__(self):
return self
def __next__(self):
result = self.get_next()
if result is None:
raise StopIteration
return result
def __len__(self):
raise NotImplementedError
def set_range(self, start_index: int, end_index: int):
raise NotImplementedError
class CalibraterBase:
def __init__(
self,
model_path: Union[str, Path],
op_types_to_calibrate: Optional[Sequence[str]] = None,
augmented_model_path="augmented_model.onnx",
symmetric=False,
use_external_data_format=False,
per_channel=False,
):
"""
:param model_path: ONNX model to calibrate. It should be a model file path
:param op_types_to_calibrate: operator types to calibrate. By default, calibrate all the float32/float16 tensors.
:param augmented_model_path: save augmented model to this path.
:param symmetric: make range of tensor symmetric (central point is 0).
:param use_external_data_format: use external data format to store model which size is >= 2Gb.
:param per_channel: whether to compute ranges per each channel.
"""
if isinstance(model_path, str):
self.model = load_model_with_shape_infer(Path(model_path))
elif isinstance(model_path, Path):
self.model = load_model_with_shape_infer(model_path)
else:
raise ValueError("model_path should be model path.")
self.op_types_to_calibrate = op_types_to_calibrate
self.augmented_model_path = augmented_model_path
self.symmetric = symmetric
self.use_external_data_format = use_external_data_format
self.per_channel = per_channel
self.augment_model = None
self.infer_session = None
self.execution_providers = ["CPUExecutionProvider"]
def set_execution_providers(self, execution_providers=["CPUExecutionProvider"]): # noqa: B006
"""
reset the execution providers to execute the collect_data. It triggers to re-creating inference session.
"""
self.execution_providers = execution_providers
self.create_inference_session()
def create_inference_session(self):
"""
create an OnnxRuntime InferenceSession.
"""
sess_options = onnxruntime.SessionOptions()
sess_options.graph_optimization_level = onnxruntime.GraphOptimizationLevel.ORT_DISABLE_ALL
self.infer_session = onnxruntime.InferenceSession(
self.augmented_model_path,
sess_options=sess_options,
providers=self.execution_providers,
)
def select_tensors_to_calibrate(self, model: ModelProto):
"""
select input/output tensors of candidate nodes to calibrate.
returns:
tensors (set): set of tensor name.
value_infos (dict): tensor name to value info.
"""
value_infos = {vi.name: vi for vi in model.graph.value_info}
value_infos.update({ot.name: ot for ot in model.graph.output})
value_infos.update({it.name: it for it in model.graph.input})
initializer = {init.name for init in model.graph.initializer}
tensors_to_calibrate = set()
tensor_type_to_calibrate = {TensorProto.FLOAT, TensorProto.FLOAT16}
for node in model.graph.node:
if not self.op_types_to_calibrate or node.op_type in self.op_types_to_calibrate:
for tensor_name in itertools.chain(node.input, node.output):
if tensor_name in value_infos:
vi = value_infos[tensor_name]
if (
vi.type.HasField("tensor_type")
and (vi.type.tensor_type.elem_type in tensor_type_to_calibrate)
and (tensor_name not in initializer)
):
tensors_to_calibrate.add(tensor_name)
return tensors_to_calibrate, value_infos
def get_augment_model(self):
"""
return: augmented onnx model. Call after calling augment_graph
"""
return self.model
def augment_graph(self):
"""
abstract method: augment the input model to prepare for collecting data. It will:
1. augment the model to be able to collect desired statistics data
2. save augmented model to augmented_model_paths
"""
raise NotImplementedError
def collect_data(self, data_reader: CalibrationDataReader):
"""
abstract method: collect the tensors that will be used for range computation. It can be called multiple times.
"""
raise NotImplementedError
def compute_data(self) -> TensorsData:
"""
abstract method: compute data based on the calibration method stored in TensorsData
"""
raise NotImplementedError
class MinMaxCalibrater(CalibraterBase):
def __init__(
self,
model_path: Union[str, Path],
op_types_to_calibrate: Optional[Sequence[str]] = None,
augmented_model_path="augmented_model.onnx",
symmetric=False,
use_external_data_format=False,
moving_average=False,
averaging_constant=0.01,
max_intermediate_outputs=None,
per_channel=False,
):
"""
:param model_path: ONNX model to calibrate. It is a model path
:param op_types_to_calibrate: operator types to calibrate. By default, calibrate all the float32/float16 tensors.
:param augmented_model_path: save augmented model to this path.
:param symmetric: make range of tensor symmetric (central point is 0).
:param use_external_data_format: use external data format to store model which size is >= 2Gb
:param moving_average: compute the moving average of the minimum and maximum values instead of the global minimum and maximum.
:param averaging_constant: constant smoothing factor to use when computing the moving average.
:param max_intermediate_outputs: maximum number of intermediate outputs before an intermediate range is computed.
:param per_channel: whether to compute ranges per each channel.
"""
super().__init__(
model_path,
op_types_to_calibrate=op_types_to_calibrate,
augmented_model_path=augmented_model_path,
symmetric=symmetric,
use_external_data_format=use_external_data_format,
per_channel=per_channel,
)
self.intermediate_outputs = []
self.calibrate_tensors_range = None
self.num_model_outputs = len(self.model.graph.output)
self.model_original_outputs = {output.name for output in self.model.graph.output}
self.moving_average = moving_average
if moving_average and (averaging_constant < 0 or averaging_constant > 1):
raise ValueError("Invalid averaging constant, which should not be < 0 or > 1.")
self.averaging_constant = averaging_constant
self.max_intermediate_outputs = max_intermediate_outputs
def augment_graph(self):
"""
Adds ReduceMin and ReduceMax nodes to all quantization_candidates op type nodes in
model and ensures their outputs are stored as part of the graph output
:return: augmented ONNX model
"""
tensors, _ = self.select_tensors_to_calibrate(self.model)
reshape_shape_name = str(uuid.uuid4())
reshape_shape = numpy_helper.from_array(np.array([-1], dtype=np.int64), reshape_shape_name)
self.model.graph.initializer.append(reshape_shape)
def get_op_version(op_type, model):
for opset_import in model.opset_import:
if onnx.defs.has(op_type, opset_import.domain):
return opset_import.version
raise RuntimeError(f"Model does not contain a version for '{op_type}'.")
def add_reduce_min_max(tensor_name, reduce_op_name):
# When doing ReduceMax/ReduceMin, ORT can't reduce on dim with value of 0 if 'keepdims' is false.
# To make the code simple, we always let keepdims to be 1.
keepdims = 1
# Adding ReduceMin/ReduceMax nodes: ReduceMin/ReduceMax -> Reshape-> (output)
reduce_output = tensor_name + "_" + reduce_op_name
intermediate_output = reduce_output + "_Reshape"
reduce_node = onnx.helper.make_node(
reduce_op_name, [tensor_name], [intermediate_output], keepdims=keepdims, name=reduce_output
)
reshape_node = onnx.helper.make_node(
"Reshape",
inputs=[intermediate_output, reshape_shape_name],
outputs=[reduce_output],
name=intermediate_output,
)
value_infos = {vi.name: vi for vi in self.model.graph.value_info}
value_infos.update({o.name: o for o in self.model.graph.output})
value_infos.update({i.name: i for i in self.model.graph.input})
if tensor_name in value_infos:
onnx_type = value_infos[tensor_name].type.tensor_type.elem_type
else:
raise ValueError(
f"Unable to guess tensor type for tensor {tensor_name!r}, "
f"running shape inference before quantization may resolve this issue."
)
# Include axes in reduce_op when per_channel, always keeping axis=1
if self.per_channel:
tensor_rank = len(value_infos[tensor_name].type.tensor_type.shape.dim)
reduced_axes = [0, *range(2, tensor_rank)]
# Depending on opset version, axes in ReduceMin/ReduceMax are in attribute or inputs
if get_op_version(reduce_op_name, self.model) < 18:
reduce_node.attribute.append(helper.make_attribute("axes", reduced_axes))
else:
reduce_axes_name = str(uuid.uuid4())
reduce_axes = numpy_helper.from_array(np.array(reduced_axes, dtype=np.int64), reduce_axes_name)
reduce_node.input.append(reduce_axes_name)
self.model.graph.initializer.append(reduce_axes)
self.model.graph.node.extend([reduce_node, reshape_node])
self.model.graph.output.append(helper.make_tensor_value_info(reduce_output, onnx_type, [None]))
for tensor in tensors:
add_reduce_min_max(tensor, "ReduceMin")
add_reduce_min_max(tensor, "ReduceMax")
onnx.save(
self.model,
self.augmented_model_path,
save_as_external_data=self.use_external_data_format,
)
def clear_collected_data(self):
self.intermediate_outputs = []
def collect_data(self, data_reader: CalibrationDataReader):
while True:
inputs = data_reader.get_next()
if not inputs:
break
self.intermediate_outputs.append(self.infer_session.run(None, inputs))
if (
self.max_intermediate_outputs is not None
and len(self.intermediate_outputs) == self.max_intermediate_outputs
):
self.clear_collected_data()
if len(self.intermediate_outputs) == 0 and self.calibrate_tensors_range is None:
raise ValueError("No data is collected.")
t = self.compute_data()
if not isinstance(t, TensorsData):
raise TypeError(f"compute_data must return a TensorsData not {type(t)}.")
self.clear_collected_data()
def merge_range(self, old_range, new_range):
if not old_range:
return new_range
for key, value in old_range.items():
# Handling for structured data types with TensorData
if isinstance(value, TensorData):
old_min = value.range_value[0]
old_max = value.range_value[1]
else:
old_min, old_max = value
if isinstance(new_range[key], TensorData):
new_min = new_range[key].range_value[0]
new_max = new_range[key].range_value[1]
else:
new_min, new_max = new_range[key]
if self.moving_average:
min_value = old_min + self.averaging_constant * (new_min - old_min)
max_value = old_max + self.averaging_constant * (new_max - old_max)
else:
min_value = min(old_min, new_min)
max_value = max(old_max, new_max)
# If structured as TensorData, wrap the result accordingly
if isinstance(value, TensorData) or isinstance(new_range[key], TensorData):
new_range[key] = TensorData(lowest=min_value, highest=max_value)
else:
new_range[key] = (min_value, max_value)
return new_range
def compute_data(self) -> TensorsData:
"""
Compute the min-max range of tensor
:return: dictionary mapping: {added node names: (ReduceMin, ReduceMax) pairs }
"""
if len(self.intermediate_outputs) == 0:
return self.calibrate_tensors_range
output_names = [self.infer_session.get_outputs()[i].name for i in range(len(self.intermediate_outputs[0]))]
output_dicts_list = [
dict(zip(output_names, intermediate_output)) for intermediate_output in self.intermediate_outputs
]
merged_output_dict = {}
for d in output_dicts_list:
for k, v in d.items():
merged_output_dict.setdefault(k, []).append(v)
added_output_names = output_names[self.num_model_outputs :]
calibrate_tensor_names = [
added_output_names[i].rpartition("_")[0] for i in range(0, len(added_output_names), 2)
] # output names
merged_added_output_dict = {
i: merged_output_dict[i] for i in merged_output_dict if i not in self.model_original_outputs
}
pairs = []
for i in range(0, len(added_output_names), 2):
if self.moving_average:
min_value_array = np.mean(merged_added_output_dict[added_output_names[i]], axis=0)
max_value_array = np.mean(merged_added_output_dict[added_output_names[i + 1]], axis=0)
else:
min_value_array = np.min(merged_added_output_dict[added_output_names[i]], axis=0)
max_value_array = np.max(merged_added_output_dict[added_output_names[i + 1]], axis=0)
if self.symmetric:
max_absolute_value = np.max([np.abs(min_value_array), np.abs(max_value_array)], axis=0)
pairs.append(tuple([-max_absolute_value, max_absolute_value]))
else:
pairs.append(tuple([min_value_array, max_value_array]))
new_calibrate_tensors_range = TensorsData(CalibrationMethod.MinMax, dict(zip(calibrate_tensor_names, pairs)))
if self.calibrate_tensors_range:
self.calibrate_tensors_range = self.merge_range(self.calibrate_tensors_range, new_calibrate_tensors_range)
else:
self.calibrate_tensors_range = new_calibrate_tensors_range
return self.calibrate_tensors_range
class HistogramCalibrater(CalibraterBase):
def __init__(
self,
model_path: Union[str, Path],
op_types_to_calibrate: Optional[Sequence[str]] = None,
augmented_model_path="augmented_model.onnx",
use_external_data_format=False,
method="percentile",
symmetric=False,
num_bins=128,
num_quantized_bins=2048,
percentile=99.999,
scenario="same",
):
"""
:param model_path: ONNX model to calibrate. It is a model path.
:param op_types_to_calibrate: operator types to calibrate. By default, calibrate all the float32/float16 tensors.
:param augmented_model_path: save augmented model to this path.
:param use_external_data_format: use external data format to store model which size is >= 2Gb
:param method: A string. One of ['entropy', 'percentile'].
:param symmetric: make range of tensor symmetric (central point is 0).
:param num_bins: number of bins to create a new histogram for collecting tensor values.
:param num_quantized_bins: number of quantized bins. Default 128.
:param percentile: A float number between [0, 100]. Default 99.99.
:param scenario: see :class:`DistributionCalibrater`
"""
super().__init__(
model_path,
op_types_to_calibrate=op_types_to_calibrate,
augmented_model_path=augmented_model_path,
symmetric=symmetric,
use_external_data_format=use_external_data_format,
)
self.intermediate_outputs = []
self.calibrate_tensors_range = None
self.num_model_outputs = len(self.model.graph.output)
self.model_original_outputs = {output.name for output in self.model.graph.output}
self.collector = None
self.method = method
self.num_bins = num_bins
self.num_quantized_bins = num_quantized_bins
self.percentile = percentile
self.tensors_to_calibrate = None
self.scenario = scenario
def augment_graph(self):
"""
make all quantization_candidates op type nodes as part of the graph output.
:return: augmented ONNX model
"""
self.tensors_to_calibrate, value_infos = self.select_tensors_to_calibrate(self.model)
for tensor in self.tensors_to_calibrate:
if tensor not in self.model_original_outputs:
self.model.graph.output.append(value_infos[tensor])
onnx.save(
self.model,
self.augmented_model_path,
save_as_external_data=self.use_external_data_format,
)
def clear_collected_data(self):
self.intermediate_outputs = []
def collect_data(self, data_reader: CalibrationDataReader):
"""
Entropy Calibrator collects operators' tensors as well as generates tensor histogram for each operator.
"""
while True:
inputs = data_reader.get_next()
if not inputs:
break
self.intermediate_outputs.append(self.infer_session.run(None, inputs))
if len(self.intermediate_outputs) == 0:
raise ValueError("No data is collected.")
output_names = [self.infer_session.get_outputs()[i].name for i in range(len(self.intermediate_outputs[0]))]
output_dicts_list = [
dict(zip(output_names, intermediate_output)) for intermediate_output in self.intermediate_outputs
]
merged_dict = {}
for d in output_dicts_list:
for k, v in d.items():
merged_dict.setdefault(k, []).append(v)
clean_merged_dict = {i: merged_dict[i] for i in merged_dict if i in self.tensors_to_calibrate}
if not self.collector:
self.collector = HistogramCollector(
method=self.method,
symmetric=self.symmetric,
num_bins=self.num_bins,
num_quantized_bins=self.num_quantized_bins,
percentile=self.percentile,
scenario=self.scenario,
)
self.collector.collect(clean_merged_dict)
self.clear_collected_data()
def compute_data(self) -> TensorsData:
"""
Compute the min-max range of tensor
:return: dictionary mapping: {tensor name: (min value, max value)}
"""
if not self.collector:
raise ValueError("No collector created and can't generate calibration data.")
if isinstance(self, EntropyCalibrater):
cal = CalibrationMethod.Entropy
elif isinstance(self, PercentileCalibrater):
cal = CalibrationMethod.Percentile
elif isinstance(self, DistributionCalibrater):
cal = CalibrationMethod.Distribution
else:
raise TypeError(f"Unknown calibrater {type(self)}. This method must be overwritten.")
return TensorsData(cal, self.collector.compute_collection_result())
class EntropyCalibrater(HistogramCalibrater):
def __init__(
self,
model_path: Union[str, Path],
op_types_to_calibrate: Optional[Sequence[str]] = None,
augmented_model_path="augmented_model.onnx",
use_external_data_format=False,
method="entropy",
symmetric=False,
num_bins=128,
num_quantized_bins=128,
):
"""
:param model_path: ONNX model to calibrate. It is a model path
:param op_types_to_calibrate: operator types to calibrate. By default, calibrate all the float32/float16 tensors.
:param augmented_model_path: save augmented model to this path.
:param use_external_data_format: use external data format to store model which size is >= 2Gb
:param method: A string. One of ['entropy', 'percentile', 'distribution'].
:param symmetric: make range of tensor symmetric (central point is 0).
:param num_bins: number of bins to create a new histogram for collecting tensor values.
:param num_quantized_bins: number of quantized bins. Default 128.
"""
super().__init__(
model_path,
op_types_to_calibrate,
augmented_model_path,
use_external_data_format,
method=method,
symmetric=symmetric,
num_bins=num_bins,
num_quantized_bins=num_quantized_bins,
)
class PercentileCalibrater(HistogramCalibrater):
def __init__(
self,
model_path: Union[str, Path],
op_types_to_calibrate: Optional[Sequence[str]] = None,
augmented_model_path="augmented_model.onnx",
use_external_data_format=False,
method="percentile",
symmetric=False,
num_bins=2048,
percentile=99.999,
):
"""
:param model_path: ONNX model to calibrate. It is a model path
:param op_types_to_calibrate: operator types to calibrate. By default, calibrate all the float32/float16 tensors.
:param augmented_model_path: save augmented model to this path.
:param use_external_data_format: use external data format to store model which size is >= 2Gb
:param method: A string. One of ['entropy', 'percentile', 'distribution'].
:param symmetric: make range of tensor symmetric (central point is 0).
:param num_quantized_bins: number of quantized bins. Default 128.
:param percentile: A float number between [0, 100]. Default 99.99.
"""
super().__init__(
model_path,
op_types_to_calibrate,
augmented_model_path,
use_external_data_format,
method=method,
symmetric=symmetric,
num_bins=num_bins,
percentile=percentile,
)
class DistributionCalibrater(HistogramCalibrater):
def __init__(
self,
model_path: Union[str, Path],
op_types_to_calibrate: Optional[Sequence[str]] = None,
augmented_model_path="augmented_model.onnx",
use_external_data_format=False,
method="distribution",
num_bins=128,
scenario="same",
):
"""
:param model_path: ONNX model to calibrate. It is a model path
:param op_types_to_calibrate: operator types to calibrate. By default, calibrate all the float32/float16 tensors.
:param augmented_model_path: save augmented model to this path.
:param use_external_data_format: use external data format to store model which size is >= 2Gb
:param method: A string. One of ['entropy', 'percentile', 'distribution'].
:param symmetric: make range of tensor symmetric (central point is 0).
:param num_bins: number of bins to create a new histogram for collecting tensor values.
:param scenario: for float 8 only, if `scenario="same"`,
the algorithm weights and float 8 follow the same distribution,
if `scenario="p3"`, it assumes the weights follow
a gaussian law and float 8 ~ X^3 where X is a gaussian law
"""
super().__init__(
model_path,
op_types_to_calibrate,
augmented_model_path,
use_external_data_format,
method=method,
num_bins=num_bins,
scenario=scenario,
)
class CalibrationDataCollector(metaclass=abc.ABCMeta):
"""
Base class for collecting data for calibration-based quantization.
"""
@abc.abstractmethod
def collect(self, name_to_arr):
"""
Generate informative data based on given data.
name_to_arr : dict
tensor name to NDArray data
"""
raise NotImplementedError
@abc.abstractmethod
def compute_collection_result(self):
"""
Get the optimal result among collection data.
"""
raise NotImplementedError
class HistogramCollector(CalibrationDataCollector):
"""
Collecting histogram for each tensor. Percentile and Entropy method are supported.
ref: https://github.com//apache/incubator-mxnet/blob/master/python/mxnet/contrib/quantization.py
ref: https://docs.nvidia.com/deeplearning/tensorrt/pytorch-quantization-toolkit/docs/_modules/
pytorch_quantization/calib/histogram.html
"""
def __init__(self, method, symmetric, num_bins, num_quantized_bins, percentile, scenario):
self.histogram_dict = {}
self.method = method
self.symmetric = symmetric
self.num_bins = num_bins
self.num_quantized_bins = num_quantized_bins
self.percentile = percentile
self.scenario = scenario
def get_histogram_dict(self):
return self.histogram_dict
def collect(self, name_to_arr):
print("Collecting tensor data and making histogram ...")
# TODO: Currently we have different collect() for entropy and percentile method respectively.
# Need unified collect in the future.
if self.method in {"distribution", "entropy"}:
return self.collect_value(name_to_arr)
elif self.method == "percentile":
if self.symmetric:
return self.collect_absolute_value(name_to_arr)
else:
return self.collect_value(name_to_arr)
else:
raise ValueError("Only 'entropy', 'percentile' or 'distribution' methods are supported")
def collect_absolute_value(self, name_to_arr):
"""
Collect histogram on absolute value
"""
for tensor, data_arr in name_to_arr.items():
if isinstance(data_arr, list):
for arr in data_arr:
assert isinstance(arr, np.ndarray), f"Unexpected type {type(arr)} for tensor={tensor!r}"
dtypes = set(a.dtype for a in data_arr)
assert (
len(dtypes) == 1
), f"The calibration expects only one element type but got {dtypes} for tensor={tensor!r}"
data_arr_np = np.asarray(data_arr)
elif not isinstance(data_arr, np.ndarray):
raise ValueError(f"Unexpected type {type(data_arr)} for tensor={tensor!r}")
else:
data_arr_np = data_arr
data_arr_np = data_arr_np.flatten()
if data_arr_np.size > 0:
min_value = np.min(data_arr_np)
max_value = np.max(data_arr_np)
else:
min_value = np.array(0, dtype=data_arr_np.dtype)
max_value = np.array(0, dtype=data_arr_np.dtype)
data_arr_np = np.absolute(data_arr_np) # only consider absolute value
if tensor not in self.histogram_dict:
# first time it uses num_bins to compute histogram.
hist, hist_edges = np.histogram(data_arr_np, bins=self.num_bins)
hist_edges = hist_edges.astype(data_arr_np.dtype)
assert (
data_arr_np.dtype != np.float64
), "only float32 or float16 is supported, every constant must be explicitly typed"
self.histogram_dict[tensor] = (hist, hist_edges, min_value, max_value)
else:
old_histogram = self.histogram_dict[tensor]
old_min = old_histogram[2]
old_max = old_histogram[3]
assert hasattr(old_min, "dtype"), f"old_min should be a numpy array but is {type(old_min)}"
assert hasattr(old_max, "dtype"), f"old_min should be a numpy array but is {type(old_max)}"
old_hist = old_histogram[0]
old_hist_edges = old_histogram[1]
temp_amax = np.max(data_arr_np)
if temp_amax > old_hist_edges[-1]:
# increase the number of bins
width = old_hist_edges[1] - old_hist_edges[0]
# NOTE: np.arange may create an extra bin after the one containing temp_amax
new_bin_edges = np.arange(old_hist_edges[-1] + width, temp_amax + width, width)
old_hist_edges = np.hstack((old_hist_edges, new_bin_edges))
hist, hist_edges = np.histogram(data_arr_np, bins=old_hist_edges)
hist_edges = hist_edges.astype(data_arr_np.dtype)
hist[: len(old_hist)] += old_hist
assert (
data_arr_np.dtype != np.float64
), "only float32 or float16 is supported, every constant must be explicitly typed"
self.histogram_dict[tensor] = (hist, hist_edges, min(old_min, min_value), max(old_max, max_value))
def collect_value(self, name_to_arr):
"""
Collect histogram on real value
"""
for tensor, data_arr in name_to_arr.items():
data_arr = np.asarray(data_arr) # noqa: PLW2901
data_arr = data_arr.flatten() # noqa: PLW2901
if data_arr.size > 0:
min_value = np.min(data_arr)
max_value = np.max(data_arr)
else:
min_value = np.array(0, dtype=data_arr.dtype)
max_value = np.array(0, dtype=data_arr.dtype)
threshold = np.array(max(abs(min_value), abs(max_value)), dtype=data_arr.dtype)
if tensor in self.histogram_dict:
old_histogram = self.histogram_dict[tensor]
self.histogram_dict[tensor] = self.merge_histogram(
old_histogram, data_arr, min_value, max_value, threshold
)
else:
hist, hist_edges = np.histogram(data_arr, self.num_bins, range=(-threshold, threshold))
self.histogram_dict[tensor] = (
hist,
hist_edges,
min_value,
max_value,
threshold,
)
def merge_histogram(self, old_histogram, data_arr, new_min, new_max, new_threshold):
(old_hist, old_hist_edges, old_min, old_max, old_threshold) = old_histogram
if new_threshold <= old_threshold:
new_hist, _ = np.histogram(data_arr, len(old_hist), range=(-old_threshold, old_threshold))
return (
new_hist + old_hist,
old_hist_edges,
min(old_min, new_min),
max(old_max, new_max),
old_threshold,
)
else:
if old_threshold == 0:
hist, hist_edges = np.histogram(data_arr, len(old_hist), range=(-new_threshold, new_threshold))
hist += old_hist
else:
old_num_bins = len(old_hist)
old_stride = 2 * old_threshold / old_num_bins
half_increased_bins = int((new_threshold - old_threshold) // old_stride + 1)
new_num_bins = old_num_bins + 2 * half_increased_bins
new_threshold = half_increased_bins * old_stride + old_threshold
hist, hist_edges = np.histogram(data_arr, new_num_bins, range=(-new_threshold, new_threshold))
hist[half_increased_bins : new_num_bins - half_increased_bins] += old_hist
return (
hist,
hist_edges,
min(old_min, new_min),
max(old_max, new_max),
new_threshold,
)
def compute_collection_result(self):
if not self.histogram_dict or len(self.histogram_dict) == 0:
raise ValueError("Histogram has not been collected. Please run collect() first.")
print(f"Finding optimal threshold for each tensor using {self.method!r} algorithm ...")
if self.method == "entropy":
return self.compute_entropy()
elif self.method == "percentile":
return self.compute_percentile()
elif self.method == "distribution":
return self.compute_distribution()
else:
raise ValueError("Only 'entropy', 'percentile' or 'distribution' methods are supported")
def compute_percentile(self):
if self.percentile < 0 or self.percentile > 100:
raise ValueError("Invalid percentile. Must be in range 0 <= percentile <= 100.")
histogram_dict = self.histogram_dict
percentile = self.percentile
thresholds_dict = {} # per tensor thresholds
print(f"Number of tensors : {len(histogram_dict)}")
print(f"Number of histogram bins : {self.num_bins}")
print(f"Percentile : ({100.0 - percentile},{percentile})")
for tensor, histogram in histogram_dict.items():
hist = histogram[0]
hist_edges = histogram[1]
total = hist.sum()
cdf = np.cumsum(hist / total)
if self.symmetric:
idx_right = np.searchsorted(cdf, percentile / 100.0)
thresholds_dict[tensor] = (
-np.array(hist_edges[idx_right], dtype=hist_edges.dtype),
np.array(hist_edges[idx_right], dtype=hist_edges.dtype),
)
else:
percent_to_cut_one_side = (100.0 - percentile) / 200.0
idx_right = np.searchsorted(cdf, 1.0 - percent_to_cut_one_side)
idx_left = np.searchsorted(cdf, percent_to_cut_one_side)
thresholds_dict[tensor] = (
np.array(hist_edges[idx_left], dtype=hist_edges.dtype),
np.array(hist_edges[idx_right], dtype=hist_edges.dtype),
)
min_value = histogram[2]
max_value = histogram[3]
if thresholds_dict[tensor][0] < min_value:
thresholds_dict[tensor] = (min_value, thresholds_dict[tensor][1])
if thresholds_dict[tensor][1] > max_value:
thresholds_dict[tensor] = (thresholds_dict[tensor][0], max_value)
thresholds_dict[tensor] = (*thresholds_dict[tensor], *hist[:2])
# Plot histogram for debug only
if os.environ.get("QUANTIZATION_DEBUG", 0) in (1, "1"):
apply_plot(hist, hist_edges)
return thresholds_dict
def compute_entropy(self):
histogram_dict = self.histogram_dict
num_quantized_bins = self.num_quantized_bins
thresholds_dict = {} # per tensor thresholds
print(f"Number of tensors : {len(histogram_dict)}")
print(f"Number of histogram bins : {self.num_bins} (The number may increase depends on the data it collects)")
print(f"Number of quantized bins : {self.num_quantized_bins}")
for tensor, histogram in histogram_dict.items():
optimal_threshold = self.get_entropy_threshold(histogram, num_quantized_bins)
thresholds_dict[tensor] = optimal_threshold
thresholds_dict[tensor] = (*optimal_threshold, *histogram[:2])
# Plot histogram for debug only
if os.environ.get("QUANTIZATION_DEBUG", 0) in (1, "1"):
apply_plot(histogram[0], histogram[1])
return thresholds_dict
@staticmethod
def _avg_std(hist, hist_edges, power=1):
if power <= 0:
raise ValueError(f"power={power} <= 0 is invalid.")
values = (hist_edges[:-1] + hist_edges[1:]) * 0.5
if power == 1:
avg = (hist * values).sum() / hist.sum()
std = ((hist * values**2).sum() / hist.sum() - avg**2) ** 0.5
return np.array(avg, dtype=hist_edges.dtype), np.array(std, dtype=hist_edges.dtype)
if int(power) == power and int(power) % 2 == 1:
avg = (hist * values**power).sum() / hist.sum()
std = ((hist * (values**power - avg) ** 2).sum() / hist.sum()) ** 0.5
return np.array(avg, dtype=hist_edges.dtype), np.array(std, dtype=hist_edges.dtype)
fact = np.abs(values) / values
fact[np.isnan(fact)] = 1
fact[np.isinf(fact)] = 1
values = np.abs(values) ** power * fact
avg = (hist * values).sum() / hist.sum()
std = ((hist * values**2).sum() / hist.sum() - avg**2) ** 0.5
return np.array(avg, dtype=hist_edges.dtype), np.array(std, dtype=hist_edges.dtype)
def compute_distribution(self):
if self.num_bins < 512:
raise ValueError("Invalid num_bins. Must be in range 512 <= num_bins.")
histogram_dict = self.histogram_dict
thresholds_dict = {} # per tensor thresholds
print(f"Number of tensors : {len(histogram_dict)}")
print(f"Number of histogram bins : {self.num_bins}")
print(f"Scenario : {self.scenario!r})")
for tensor, histogram in histogram_dict.items():
hist = histogram[0]
hist_edges = histogram[1]
assert hist_edges.dtype != np.float64
if self.scenario == "same":
avg_coef, std_coef = self._avg_std(hist, hist_edges, power=1)
elif self.scenario == "p3":
avg_coef, std_coef = self._avg_std(hist, hist_edges, power=1.0 / 3.0)
else:
raise ValueError("Invalid scenario. Must be in {'same', 'p3'}.")
assert avg_coef.dtype != np.float64
assert std_coef.dtype != np.float64
assert hist_edges.dtype != np.float64
thresholds_dict[tensor] = TensorData(
avg=avg_coef,
std=std_coef,
hist=hist,
hist_edges=hist_edges,
lowest=hist_edges.min(),
highest=hist_edges.max(),
)
# Plot histogram for debug only
if os.environ.get("QUANTIZATION_DEBUG", 0) in (1, "1"):
apply_plot(hist, hist_edges)
return thresholds_dict
def get_entropy_threshold(self, histogram, num_quantized_bins):
"""Given a dataset, find the optimal threshold for quantizing it.
The reference distribution is `q`, and the candidate distribution is `p`.
`q` is a truncated version of the original distribution.
Ref: http://on-demand.gputechconf.com/gtc/2017/presentation/s7310-8-bit-inference-with-tensorrt.pdf
"""
hist = histogram[0]
hist_edges = histogram[1]
num_bins = hist.size
zero_bin_index = num_bins // 2
num_half_quantized_bin = num_quantized_bins // 2
dtype = histogram[1].dtype
kl_divergence = np.zeros(zero_bin_index - num_half_quantized_bin + 1)
thresholds = [(np.array(0, dtype=dtype), np.array(0, dtype=dtype)) for i in range(kl_divergence.size)]
# <------------ num bins ---------------->
# <--- quantized bins ---->
# |======|===========|===========|=======|
# zero bin index
# ^ ^
# | |
# start index end index (start of iteration)
# ^ ^
# | |
# start index end index ...
# ^ ^
# | |
# start index end index (end of iteration)
for i in range(num_half_quantized_bin, zero_bin_index + 1, 1):
start_index = zero_bin_index - i
end_index = min(zero_bin_index + i + 1, num_bins)
thresholds[i - num_half_quantized_bin] = (hist_edges[start_index], hist_edges[end_index])
sliced_distribution = copy.deepcopy(hist[start_index:end_index])
# reference distribution p
p = sliced_distribution.copy() # a copy of np array
left_outliers_count = sum(hist[:start_index])
right_outliers_count = sum(hist[end_index:])
p[0] += left_outliers_count
p[-1] += right_outliers_count
# nonzeros[i] incidates whether p[i] is non-zero
nonzeros = (p != 0).astype(np.int64)
# quantize p.size bins into quantized bins (default 128 bins)
quantized_bins = np.zeros(num_quantized_bins, dtype=np.int64)
num_merged_bins = sliced_distribution.size // num_quantized_bins
# merge bins into quantized bins
for index in range(num_quantized_bins):
start = index * num_merged_bins
end = start + num_merged_bins
quantized_bins[index] = sum(sliced_distribution[start:end])
quantized_bins[-1] += sum(sliced_distribution[num_quantized_bins * num_merged_bins :])
# in order to compare p and q, we need to make length of q equals to length of p
# expand quantized bins into p.size bins
q = np.zeros(p.size, dtype=np.int64)
for index in range(num_quantized_bins):
start = index * num_merged_bins
end = start + num_merged_bins
norm = sum(nonzeros[start:end])
if norm != 0:
q[start:end] = quantized_bins[index] / norm
p = smooth_distribution(p)
q = smooth_distribution(q)
if p is None or q is None:
div = np.array(np.inf, dtype=dtype)
else:
div = np.array(entropy(p, q), dtype=dtype)
kl_divergence[i - num_half_quantized_bin] = div
min_kl_divergence_idx = np.argmin(kl_divergence)
optimal_threshold = thresholds[min_kl_divergence_idx]
min_value = histogram[2]
max_value = histogram[3]
if optimal_threshold[0] < min_value:
optimal_threshold = (min_value, optimal_threshold[1])
if optimal_threshold[1] > max_value:
optimal_threshold = (optimal_threshold[0], max_value)
assert hasattr(optimal_threshold[0], "dtype")
assert hasattr(optimal_threshold[1], "dtype")
return optimal_threshold
def create_calibrator(
model: Union[str, Path],
op_types_to_calibrate: Optional[Sequence[str]] = None,
augmented_model_path="augmented_model.onnx",
calibrate_method=CalibrationMethod.MinMax,
use_external_data_format=False,
extra_options={}, # noqa: B006
):
calibrator = None
if calibrate_method == CalibrationMethod.MinMax:
# default settings for min-max algorithm
symmetric = extra_options.get("symmetric", False)
moving_average = extra_options.get("moving_average", False)
averaging_constant = extra_options.get("averaging_constant", 0.01)
max_intermediate_outputs = extra_options.get("max_intermediate_outputs", None)
per_channel = extra_options.get("per_channel", False)
calibrator = MinMaxCalibrater(
model,
op_types_to_calibrate,
augmented_model_path,
use_external_data_format=use_external_data_format,
symmetric=symmetric,
moving_average=moving_average,
averaging_constant=averaging_constant,
max_intermediate_outputs=max_intermediate_outputs,
per_channel=per_channel,
)
elif calibrate_method == CalibrationMethod.Entropy:
# default settings for entropy algorithm
num_bins = extra_options.get("num_bins", 128)
num_quantized_bins = extra_options.get("num_quantized_bins", 128)
symmetric = extra_options.get("symmetric", False)
calibrator = EntropyCalibrater(
model,
op_types_to_calibrate,
augmented_model_path,
use_external_data_format=use_external_data_format,
symmetric=symmetric,
num_bins=num_bins,
num_quantized_bins=num_quantized_bins,
)
elif calibrate_method == CalibrationMethod.Percentile:
# default settings for percentile algorithm
num_bins = extra_options.get("num_bins", 2048)
percentile = extra_options.get("percentile", 99.999)
symmetric = extra_options.get("symmetric", True)
calibrator = PercentileCalibrater(
model,
op_types_to_calibrate,
augmented_model_path,
use_external_data_format=use_external_data_format,
symmetric=symmetric,
num_bins=num_bins,
percentile=percentile,
)
elif calibrate_method == CalibrationMethod.Distribution:
# default settings for percentile algorithm
num_bins = extra_options.get("num_bins", 2048)
scenario = extra_options.get("scenario", "same")
calibrator = DistributionCalibrater(
model,
op_types_to_calibrate,
augmented_model_path,
use_external_data_format=use_external_data_format,
num_bins=num_bins,
scenario=scenario,
)
if calibrator:
calibrator.augment_graph()
calibrator.create_inference_session()
return calibrator
raise ValueError(f"Unsupported calibration method {calibrate_method}")