# Copyright (c) 2018 PaddlePaddle 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. import math import logging import numpy as np from ....executor import global_scope from .... import io from .... import core from .... import framework from ....framework import IrGraph from ....log_helper import get_logger from .quantization_pass import QuantizationTransformPass from .quantization_pass import QuantizationFreezePass from .quantization_pass import AddQuantDequantPass from .quantization_pass import _op_real_in_out_name __all__ = ['PostTrainingQuantization'] _logger = get_logger( __name__, logging.INFO, fmt='%(asctime)s-%(levelname)s: %(message)s') class PostTrainingQuantization(object): def __init__(self, executor, sample_generator, model_dir, model_filename=None, params_filename=None, batch_size=10, batch_nums=None, scope=None, algo="KL", quantizable_op_type=["conv2d", "depthwise_conv2d", "mul"], is_full_quantize=False): ''' The class utilizes post training quantization methon to quantize the fp32 model. It uses calibrate data to calculate the scale factor of quantized variables, and inserts fake quant/dequant op to obtain the quantized model. Args: executor(fluid.Executor): The executor to load, run and save the quantized model. sample_generator(Python Generator): The sample generator provides calibrate data for DataLoader, and it only returns a sample every time. model_dir(str): The path of the fp32 model that will be quantized, and the model and params files are under the path. model_filename(str, optional): The name of file to load the inference program. If it is None, the default filename '__model__' will be used. Default is 'None'. params_filename(str, optional): The name of file to load all parameters. When all parameters were saved in a single binary file, set it as the real filename. If parameters were saved in separate files, set it as 'None'. Default is 'None'. batch_size(int, optional): The batch size of DataLoader. Default is 10. batch_nums(int, optional): If batch_nums is not None, the number of calibrate data is batch_size*batch_nums. If batch_nums is None, use all data provided by sample_generator as calibrate data. scope(fluid.Scope, optional): The scope of the program, use it to load and save variables. If scope=None, get scope by global_scope(). algo(str, optional): If algo=KL, use KL-divergenc method to get the more precise scale factor. If algo='direct', use abs_max methon to get the scale factor. Default is KL. quantizable_op_type(list[str], optional): List the type of ops that will be quantized. Default is ["conv2d", "depthwise_conv2d", "mul"]. is_full_quantized(bool, optional): If set is_full_quantized as True, apply quantization to all supported quantizable op type. If set is_full_quantized as False, only apply quantization to the op type according to the input quantizable_op_type. Returns: None Examples: .. code-block:: python import paddle.fluid as fluid from paddle.fluid.contrib.slim.quantization import PostTrainingQuantization exe = fluid.Executor(fluid.CPUPlace()) model_dir = path/to/fp32_model_params # set model_filename as None when the filename is __model__, # otherwise set it as the real filename model_filename = None # set params_filename as None when all parameters were saved in # separate files, otherwise set it as the real filename params_filename = None save_model_path = path/to/save_model_path # prepare the sample generator according to the model, and the # sample generator must return a sample every time. The reference # document: https://www.paddlepaddle.org.cn/documentation/docs/zh # /user_guides/howto/prepare_data/use_py_reader.html sample_generator = your_sample_generator batch_size = 10 batch_nums = 10 algo = "KL" quantizable_op_type = ["conv2d", "depthwise_conv2d", "mul"] ptq = PostTrainingQuantization( executor=exe, sample_generator=sample_generator, model_dir=model_dir, model_filename=model_filename, params_filename=params_filename, batch_size=batch_size, batch_nums=batch_nums, algo=algo, quantizable_op_type=quantizable_op_type) ptq.quantize() ptq.save_quantized_model(save_model_path) ''' self._executor = executor self._sample_generator = sample_generator self._model_dir = model_dir self._model_filename = model_filename self._params_filename = params_filename self._batch_size = batch_size self._batch_nums = batch_nums self._scope = global_scope() if scope == None else scope self._algo = algo supported_quantizable_op_type = \ QuantizationTransformPass._supported_quantizable_op_type + \ AddQuantDequantPass._supported_quantizable_op_type if is_full_quantize: self._quantizable_op_type = supported_quantizable_op_type else: self._quantizable_op_type = quantizable_op_type for op_type in self._quantizable_op_type: assert op_type in supported_quantizable_op_type + \ AddQuantDequantPass._activation_type, \ op_type + " is not supported for quantization." self._place = self._executor.place self._program = None self._feed_list = None self._fetch_list = None self._data_loader = None self._op_real_in_out_name = _op_real_in_out_name self._bit_length = 8 self._quantized_weight_var_name = [] self._quantized_act_var_name = [] self._sampling_data = {} self._quantized_var_scale_factor = {} def quantize(self): ''' Quantize the fp32 model. Use calibrate data to calculate the scale factor of quantized variables, and inserts fake quant/dequant op to obtain the quantized model. Args: None Returns: the program of quantized model. ''' self._preprocess() batch_id = 0 for data in self._data_loader(): self._executor.run(program=self._program, feed=data, fetch_list=self._fetch_list, return_numpy=False) self._sample_data() if batch_id % 5 == 0: _logger.info("run batch: " + str(batch_id)) batch_id += 1 if self._batch_nums and batch_id >= self._batch_nums: break _logger.info("all run batch: " + str(batch_id)) _logger.info("calculate scale factor ...") self._calculate_scale_factor() _logger.info("update the program ...") self._update_program() self._save_output_scale() return self._program def save_quantized_model(self, save_model_path): ''' Save the quantized model to the disk. Args: save_model_path(str): The path to save the quantized model Returns: None ''' io.save_inference_model( dirname=save_model_path, feeded_var_names=self._feed_list, target_vars=self._fetch_list, executor=self._executor, main_program=self._program) def _preprocess(self): ''' Load model and set data loader, collect the variable names for sampling, and set activation variables to be persistable. ''' # load model and set data loader [self._program, self._feed_list, self._fetch_list] = \ io.load_inference_model(dirname=self._model_dir, executor=self._executor, model_filename=self._model_filename, params_filename=self._params_filename) feed_vars = [framework._get_var(str(var_name), self._program) \ for var_name in self._feed_list] self._data_loader = io.DataLoader.from_generator( feed_list=feed_vars, capacity=3 * self._batch_size, iterable=True) self._data_loader.set_sample_generator( self._sample_generator, batch_size=self._batch_size, drop_last=True, places=self._place) # collect the variable names for sampling persistable_var_names = [] for var in self._program.list_vars(): if var.persistable: persistable_var_names.append(var.name) for op in self._program.global_block().ops: op_type = op.type if op_type in self._quantizable_op_type: if op_type in ("conv2d", "depthwise_conv2d"): self._quantized_act_var_name.append(op.input("Input")[0]) self._quantized_weight_var_name.append( op.input("Filter")[0]) self._quantized_act_var_name.append(op.output("Output")[0]) elif op_type == "mul": if self._is_input_all_not_persistable( op, persistable_var_names): op._set_attr("skip_quant", True) _logger.warning("Skip quant a mul op for two " "input variables are not persistable") else: self._quantized_act_var_name.append(op.input("X")[0]) self._quantized_weight_var_name.append(op.input("Y")[0]) self._quantized_act_var_name.append(op.output("Out")[0]) else: # process other quantizable op type, the input must all not persistable if self._is_input_all_not_persistable( op, persistable_var_names): input_output_name_list = self._op_real_in_out_name[ op_type] for input_name in input_output_name_list[0]: for var_name in op.input(input_name): self._quantized_act_var_name.append(var_name) for output_name in input_output_name_list[1]: for var_name in op.output(output_name): self._quantized_act_var_name.append(var_name) # set activation variables to be persistable, so can obtain # the tensor data in sample_data for var in self._program.list_vars(): if var.name in self._quantized_act_var_name: var.persistable = True def _sample_data(self): ''' Sample the tensor data of quantized variables, applied in every iteration. ''' for var_name in self._quantized_weight_var_name: if var_name not in self._sampling_data: var_tensor = self._load_var_value(var_name) self._sampling_data[var_name] = var_tensor for var_name in self._quantized_act_var_name: if var_name not in self._sampling_data: self._sampling_data[var_name] = [] var_tensor = self._load_var_value(var_name) self._sampling_data[var_name].append(var_tensor) def _calculate_scale_factor(self): ''' Calculate the scale factor of quantized variables. ''' # apply channel_wise_abs_max quantization for weights for var_name in self._quantized_weight_var_name: data = self._sampling_data[var_name] scale_factor_per_channel = [] for i in range(data.shape[0]): abs_max_value = np.max(np.abs(data[i])) scale_factor_per_channel.append(abs_max_value) self._quantized_var_scale_factor[ var_name] = scale_factor_per_channel # apply kl quantization for activation for var_name in self._quantized_act_var_name: if self._algo == "KL": self._quantized_var_scale_factor[var_name] = \ self._get_kl_scaling_factor(np.abs(self._sampling_data[var_name])) else: self._quantized_var_scale_factor[var_name] = \ np.max(np.abs(self._sampling_data[var_name])) def _update_program(self): ''' Insert fake_quantize/fake_dequantize op to the program. ''' # reset quantized activation variable for var in self._program.list_vars(): if var.name in self._quantized_act_var_name: var.persistable = False # use QuantizationTransformPass to insert fake_quantize/fake_dequantize op graph = IrGraph(core.Graph(self._program.desc), for_test=True) major_quantizable_op_types = [] for op_type in QuantizationTransformPass._supported_quantizable_op_type: if op_type in self._quantizable_op_type: major_quantizable_op_types.append(op_type) transform_pass = QuantizationTransformPass( scope=self._scope, place=self._place, weight_bits=self._bit_length, activation_bits=self._bit_length, activation_quantize_type='moving_average_abs_max', weight_quantize_type='channel_wise_abs_max', quantizable_op_type=major_quantizable_op_types) transform_pass.apply(graph) # use AddQuantDequantPass to insert fake_quant_dequant op minor_quantizable_op_types = [] for op_type in AddQuantDequantPass._supported_quantizable_op_type: if op_type in self._quantizable_op_type: minor_quantizable_op_types.append(op_type) add_quant_dequant_pass = AddQuantDequantPass( scope=self._scope, place=self._place, quantizable_op_type=minor_quantizable_op_types) add_quant_dequant_pass.apply(graph) # save scale factor to scale var node for key, val in self._quantized_var_scale_factor.items(): self._set_var_node_value( key + ".scale", np.array( [val], dtype=np.float32)) self._set_var_node_value( key + ".quant_dequant.scale", np.array( [val], dtype=np.float32)) # apply QuantizationFreezePass, and obtain the final quant model freeze_pass = QuantizationFreezePass( scope=self._scope, place=self._place, weight_bits=self._bit_length, activation_bits=self._bit_length, weight_quantize_type='channel_wise_abs_max', quantizable_op_type=major_quantizable_op_types) freeze_pass.apply(graph) self._program = graph.to_program() def _save_output_scale(self): ''' Save output scale to the quantized op. ''' output_scale_name = "output_scale" for op in self._program.global_block().ops: if op.type in self._quantizable_op_type: output_name_list = self._op_real_in_out_name[op.type][1] for output_name in output_name_list: for output_var_name in op.output(output_name): if output_var_name in self._quantized_var_scale_factor: op._set_attr(output_scale_name, self._quantized_var_scale_factor[ output_var_name]) def _load_var_value(self, var_name): ''' Load variable value from scope ''' return np.array(self._scope.find_var(var_name).get_tensor()) def _set_var_node_value(self, var_node_name, np_value): ''' Set the value of var node by name, if the node exits, ''' assert isinstance(np_value, np.ndarray), \ 'The type of value should be numpy array.' var_node = self._scope.find_var(var_node_name) if var_node != None: tensor = var_node.get_tensor() tensor.set(np_value, self._place) def _is_input_all_not_persistable(self, op, persistable_var_names): ''' Analyze the real inputs of the op are all not persistable. ''' is_input_all_not_persistable = True input_name_list = self._op_real_in_out_name[op.type][0] for input_name in input_name_list: for var_name in op.input(input_name): if var_name in persistable_var_names: is_input_all_not_persistable = False break return is_input_all_not_persistable def _get_kl_scaling_factor(self, activation_blob, num_quantized_bins=255): ''' Using the KL-divergenc method to get the more precise scaling factor. ''' max_val = np.max(activation_blob) min_val = np.min(activation_blob) if min_val >= 0: hist, hist_edeges = np.histogram( activation_blob, bins=2048, range=(min_val, max_val)) ending_iter = 2047 starting_iter = int(ending_iter * 0.7) else: _logger.error("Please first apply abs to activation_blob.") bin_width = hist_edeges[1] - hist_edeges[0] P_sum = len(np.array(activation_blob).ravel()) min_kl_divergence = 0 min_kl_index = 0 kl_inited = False for i in range(starting_iter, ending_iter + 1): reference_distr_P = hist[0:i].tolist() outliers_count = sum(hist[i:2048]) if reference_distr_P[i - 1] == 0: continue reference_distr_P[i - 1] += outliers_count reference_distr_bins = reference_distr_P[:] candidate_distr_Q = hist[0:i].tolist() num_merged_bins = int(i / num_quantized_bins) candidate_distr_Q_quantized = [0] * num_quantized_bins j_start = 0 j_end = num_merged_bins for idx in range(num_quantized_bins): candidate_distr_Q_quantized[idx] = sum(candidate_distr_Q[ j_start:j_end]) j_start += num_merged_bins j_end += num_merged_bins if (idx + 1) == num_quantized_bins - 1: j_end = i candidate_distr_Q = self._expand_quantized_bins( candidate_distr_Q_quantized, reference_distr_bins) Q_sum = sum(candidate_distr_Q) kl_divergence = self._safe_entropy(reference_distr_P, P_sum, candidate_distr_Q, Q_sum) if not kl_inited: min_kl_divergence = kl_divergence min_kl_index = i kl_inited = True elif kl_divergence < min_kl_divergence: min_kl_divergence = kl_divergence min_kl_index = i else: pass if min_kl_index == 0: while starting_iter > 0: if hist[starting_iter] == 0: starting_iter -= 1 continue else: break min_kl_index = starting_iter return (min_kl_index + 0.5) * bin_width def _expand_quantized_bins(self, quantized_bins, reference_bins): ''' ''' expanded_quantized_bins = [0] * len(reference_bins) num_merged_bins = int(len(reference_bins) / len(quantized_bins)) j_start = 0 j_end = num_merged_bins for idx in range(len(quantized_bins)): zero_count = reference_bins[j_start:j_end].count(0) num_merged_bins = j_end - j_start if zero_count == num_merged_bins: avg_bin_ele = 0 else: avg_bin_ele = quantized_bins[idx] / ( num_merged_bins - zero_count + 0.0) for idx1 in range(j_start, j_end): expanded_quantized_bins[idx1] = (0 if reference_bins[idx1] == 0 else avg_bin_ele) j_start += num_merged_bins j_end += num_merged_bins if (idx + 1) == len(quantized_bins) - 1: j_end = len(reference_bins) return expanded_quantized_bins def _safe_entropy(self, reference_distr_P, P_sum, candidate_distr_Q, Q_sum): ''' Calculate the entropy. ''' assert len(reference_distr_P) == len(candidate_distr_Q) tmp_sum1 = 0 tmp_sum2 = 0 for idx in range(len(reference_distr_P)): p_idx = reference_distr_P[idx] q_idx = candidate_distr_Q[idx] if p_idx == 0: tmp_sum1 += 0 tmp_sum2 += 0 else: if q_idx == 0: _logger.error("Fatal error!, idx = " + str(idx) + " qindex = 0! p_idx = " + str(p_idx)) tmp_sum1 += p_idx * (math.log(Q_sum * p_idx)) tmp_sum2 += p_idx * (math.log(P_sum * q_idx)) return (tmp_sum1 - tmp_sum2) / P_sum