main_inception_v4.py

# -*- coding: utf-8 -*-
'''
Created on Thu Sep 20 16:16:39 2018

@ author: herbert-chen
'''
import os
import time
import shutil
import random
import numpy as np
import pandas as pd
from PIL import Image
from tqdm import tqdm
from collections import OrderedDict
from sklearn.model_selection import train_test_split

import model_v4

import torch
import torch.nn as nn
import torch.optim as optim
import torchvision.models as models
import torchvision.transforms as transforms
from torch.utils.data import Dataset, DataLoader


def main():
    # 随机种子
    np.random.seed(666)
    torch.manual_seed(666)
    torch.cuda.manual_seed_all(666)
    random.seed(666)

    # 获取当前文件名，用于创建模型及结果文件的目录
    file_name = os.path.basename(__file__).split('.')[0]
    # 创建保存模型和结果的文件夹
    if not os.path.exists('./model/%s' % file_name):
        os.makedirs('./model/%s' % file_name)
    if not os.path.exists('./result/%s' % file_name):
        os.makedirs('./result/%s' % file_name)
    # 创建日志文件
    if not os.path.exists('./result/%s.txt' % file_name):
        with open('./result/%s.txt' % file_name, 'w') as acc_file:
            pass
    with open('./result/%s.txt' % file_name, 'a') as acc_file:
        acc_file.write('\n%s %s\n' % (time.strftime("%Y-%m-%d %H:%M:%S", time.localtime(time.time())), file_name))

    # 默认使用PIL读图
    def default_loader(path):
        # return Image.open(path)
        return Image.open(path).convert('RGB')

    # 训练集图片读取
    class TrainDataset(Dataset):
        def __init__(self, label_list, transform=None, target_transform=None, loader=default_loader):
            imgs = []
            for index, row in label_list.iterrows():
                imgs.append((row['img_path'], row['label']))
            self.imgs = imgs
            self.transform = transform
            self.target_transform = target_transform
            self.loader = loader

        def __getitem__(self, index):
            filename, label = self.imgs[index]
            img = self.loader(filename)
            if self.transform is not None:
                img = self.transform(img)
            return img, label

        def __len__(self):
            return len(self.imgs)

    # 验证集图片读取
    class ValDataset(Dataset):
        def __init__(self, label_list, transform=None, target_transform=None, loader=default_loader):
            imgs = []
            for index, row in label_list.iterrows():
                imgs.append((row['img_path'], row['label']))
            self.imgs = imgs
            self.transform = transform
            self.target_transform = target_transform
            self.loader = loader

        def __getitem__(self, index):
            filename, label = self.imgs[index]
            img = self.loader(filename)
            if self.transform is not None:
                img = self.transform(img)
            return img, label

        def __len__(self):
            return len(self.imgs)

    # 测试集图片读取
    class TestDataset(Dataset):
        def __init__(self, label_list, transform=None, target_transform=None, loader=default_loader):
            imgs = []
            for index, row in label_list.iterrows():
                imgs.append((row['img_path']))
            self.imgs = imgs
            self.transform = transform
            self.target_transform = target_transform
            self.loader = loader

        def __getitem__(self, index):
            filename = self.imgs[index]
            img = self.loader(filename)
            if self.transform is not None:
                img = self.transform(img)
            return img, filename

        def __len__(self):
            return len(self.imgs)

    # 数据增强：在给定角度中随机进行旋转
    class FixedRotation(object):
        def __init__(self, angles):
            self.angles = angles

        def __call__(self, img):
            return fixed_rotate(img, self.angles)

    def fixed_rotate(img, angles):
        angles = list(angles)
        angles_num = len(angles)
        index = random.randint(0, angles_num - 1)
        return img.rotate(angles[index])

    # 训练函数
    def train(train_loader, model, criterion, optimizer, epoch):
        batch_time = AverageMeter()
        data_time = AverageMeter()
        losses = AverageMeter()
        acc = AverageMeter()

        # switch to train mode
        model.train()

        end = time.time()
        # 从训练集迭代器中获取训练数据
        for i, (images, target) in enumerate(train_loader):
            # 评估图片读取耗时
            data_time.update(time.time() - end)
            # 将图片和标签转化为tensor
            image_var = torch.tensor(images).cuda(async=True)
            label = torch.tensor(target).cuda(async=True)

            # 将图片输入网络，前传，生成预测值
            y_pred = model(image_var)
            # 计算loss
            loss = criterion(y_pred, label)
            losses.update(loss.item(), images.size(0))

            # 计算top1正确率
            prec, PRED_COUNT = accuracy(y_pred.data, target, topk=(1, 1))
            acc.update(prec, PRED_COUNT)

            # 对梯度进行反向传播，使用随机梯度下降更新网络权重
            optimizer.zero_grad()
            loss.backward()
            optimizer.step()

            # 评估训练耗时
            batch_time.update(time.time() - end)
            end = time.time()

            # 打印耗时与结果
            if i % print_freq == 0:
                print('Epoch: [{0}][{1}/{2}]\t'
                      'Time {batch_time.val:.3f} ({batch_time.avg:.3f})\t'
                      'Data {data_time.val:.3f} ({data_time.avg:.3f})\t'
                      'Loss {loss.val:.4f} ({loss.avg:.4f})\t'
                      'Accuray {acc.val:.3f} ({acc.avg:.3f})'.format(
                    epoch, i, len(train_loader), batch_time=batch_time, data_time=data_time, loss=losses, acc=acc))

    # 验证函数
    def validate(val_loader, model, criterion):
        batch_time = AverageMeter()
        losses = AverageMeter()
        acc = AverageMeter()

        # switch to evaluate mode
        model.eval()

        end = time.time()
        for i, (images, labels) in enumerate(val_loader):
            image_var = torch.tensor(images).cuda(async=True)
            target = torch.tensor(labels).cuda(async=True)

            # 图片前传。验证和测试时不需要更新网络权重，所以使用torch.no_grad()，表示不计算梯度
            with torch.no_grad():
                y_pred = model(image_var)
                loss = criterion(y_pred, target)

            # measure accuracy and record loss
            prec, PRED_COUNT = accuracy(y_pred.data, labels, topk=(1, 1))
            losses.update(loss.item(), images.size(0))
            acc.update(prec, PRED_COUNT)

            # measure elapsed time
            batch_time.update(time.time() - end)
            end = time.time()

            if i % print_freq == 0:
                print('TrainVal: [{0}/{1}]\t'
                      'Time {batch_time.val:.3f} ({batch_time.avg:.3f})\t'
                      'Loss {loss.val:.4f} ({loss.avg:.4f})\t'
                      'Accuray {acc.val:.3f} ({acc.avg:.3f})'.format(
                    i, len(val_loader), batch_time=batch_time, loss=losses, acc=acc))

        print(' * Accuray {acc.avg:.3f}'.format(acc=acc), '(Previous Best Acc: %.3f)' % best_precision,
              ' * Loss {loss.avg:.3f}'.format(loss=losses), 'Previous Lowest Loss: %.3f)' % lowest_loss)
        return acc.avg, losses.avg

    # 测试函数
    def test(test_loader, model):
        csv_map = OrderedDict({'filename': [], 'probability': []})
        # switch to evaluate mode
        model.eval()
        for i, (images, filepath) in enumerate(tqdm(test_loader)):
            # bs, ncrops, c, h, w = images.size()
            filepath = [os.path.basename(i) for i in filepath]
            image_var = torch.tensor(images, requires_grad=False)  # for pytorch 0.4

            with torch.no_grad():
                y_pred = model(image_var)
                # 使用softmax函数将图片预测结果转换成类别概率
                smax = nn.Softmax(1)
                smax_out = smax(y_pred)

            # 保存图片名称与预测概率
            csv_map['filename'].extend(filepath)
            for output in smax_out:
                prob = ';'.join([str(i) for i in output.data.tolist()])
                csv_map['probability'].append(prob)

        result = pd.DataFrame(csv_map)
        result['probability'] = result['probability'].map(lambda x: [float(i) for i in x.split(';')])

        # 转换成提交样例中的格式
        sub_filename, sub_label = [], []
        for index, row in result.iterrows():
            sub_filename.append(row['filename'])
            pred_label = np.argmax(row['probability'])
            sub_label.append('dermatosis%d' % pred_label)

        # 生成结果文件，保存在result文件夹中，可用于直接提交
        submission = pd.DataFrame({'filename': sub_filename, 'label': sub_label})
        submission.to_csv('./result/%s/submission.csv' % file_name, header=None, index=False)
        return

    # 保存最新模型以及最优模型
    def save_checkpoint(state, is_best, is_lowest_loss, filename='./model/%s/checkpoint.pth.tar' % file_name):
        torch.save(state, filename)
        if is_best:
            shutil.copyfile(filename, './model/%s/model_best.pth.tar' % file_name)
        if is_lowest_loss:
            shutil.copyfile(filename, './model/%s/lowest_loss.pth.tar' % file_name)

    # 用于计算精度和时间的变化
    class AverageMeter(object):
        """Computes and stores the average and current value"""
        def __init__(self):
            self.reset()

        def reset(self):
            self.val = 0
            self.avg = 0
            self.sum = 0
            self.count = 0

        def update(self, val, n=1):
            self.val = val
            self.sum += val * n
            self.count += n
            self.avg = self.sum / self.count

    # 学习率衰减：lr = lr / lr_decay
    def adjust_learning_rate():
        nonlocal lr
        lr = lr / lr_decay
        return optim.Adam(model.parameters(), lr, weight_decay=weight_decay, amsgrad=True)

    # 计算top K准确率
    def accuracy(y_pred, y_actual, topk=(1,)):
        """Computes the precision@k for the specified values of k"""
        final_acc = 0
        maxk = max(topk)
        # for prob_threshold in np.arange(0, 1, 0.01):
        PRED_COUNT = y_actual.size(0)
        PRED_CORRECT_COUNT = 0
        prob, pred = y_pred.topk(maxk, 1, True, True)
        # prob = np.where(prob > prob_threshold, prob, 0)
        for j in range(pred.size(0)):
            if int(y_actual[j]) == int(pred[j]):
                PRED_CORRECT_COUNT += 1
        if PRED_COUNT == 0:
            final_acc = 0
        else:
            final_acc = PRED_CORRECT_COUNT / PRED_COUNT
        return final_acc * 100, PRED_COUNT

    # 程序主体

    # 设定GPU ID
    os.environ["CUDA_VISIBLE_DEVICES"] = '0'
    # 小数据集上，batch size不易过大。如出现out of memory，应调小batch size
    batch_size = 16
    # 进程数量，最好不要超过电脑最大进程数。windows下报错可以改为workers=0
    workers = 12
    valid_prob_threshold=0.4

    # epoch数量，分stage进行，跑完一个stage后降低学习率进入下一个stage
    stage_epochs = [6, 3, 3]
    # 初始学习率
    lr = 1e-4
    # 学习率衰减系数 (new_lr = lr / lr_decay)
    lr_decay = 5
    # 正则化系数
    weight_decay = 1e-4

    # 参数初始化
    stage = 0
    start_epoch = 0
    total_epochs = sum(stage_epochs)
    best_precision = 0
    lowest_loss = 100

    # 设定打印频率，即多少step打印一次，用于观察loss和acc的实时变化
    # 打印结果中，括号前面为实时loss和acc，括号内部为epoch内平均loss和acc
    print_freq = 1
    # 验证集比例
    val_ratio = 0.2
    # 是否只验证，不训练
    evaluate = False
    # 是否从断点继续跑
    resume = False
    # 创建inception_v4模型
    model = model_v4.v4(num_classes=23)
    model = torch.nn.DataParallel(model).cuda()

    #data_augmentation
    double_label = [3,6,7,8]
    triple_label = [1,9,12]


    # optionally resume from a checkpoint
    if resume:
        checkpoint_path = './model/%s/checkpoint.pth.tar' % file_name
        if os.path.isfile(checkpoint_path):
            print("=> loading checkpoint '{}'".format(checkpoint_path))
            checkpoint = torch.load(checkpoint_path)
            start_epoch = checkpoint['epoch'] + 1
            best_precision = checkpoint['best_precision']
            lowest_loss = checkpoint['lowest_loss']
            stage = checkpoint['stage']
            lr = checkpoint['lr']
            model.load_state_dict(checkpoint['state_dict'])
            # 如果中断点恰好为转换stage的点，需要特殊处理
            if start_epoch in np.cumsum(stage_epochs)[:-1]:
                stage += 1
                optimizer = adjust_learning_rate()
                model.load_state_dict(torch.load('./model/%s/model_best.pth.tar' % file_name)['state_dict'])
            print("=> loaded checkpoint (epoch {})".format(checkpoint['epoch']))
        else:
            print("=> no checkpoint found at '{}'".format(checkpoint_path))

    # 读取训练图片列表
    all_data = pd.read_csv('data/label.csv')
    # 分离训练集和测试集，stratify参数用于分层抽样
    train_data_list, val_data_list = train_test_split(all_data, test_size=val_ratio, random_state=666, stratify=all_data['label'])
    # 读取测试图片列表
    test_data_list = pd.read_csv('data/test.csv')

    # 图片归一化，由于采用ImageNet预训练网络，因此这里直接采用ImageNet网络的参数
    normalize = transforms.Normalize(mean=[0.485, 0.456, 0.406], std=[0.229, 0.224, 0.225])

    # 训练集图片变换，输入网络的尺寸为384*384
    train_data = TrainDataset(train_data_list,
                              transform=transforms.Compose([
                                  transforms.Resize((400, 400)),
                                  transforms.ColorJitter(0.15, 0.15, 0.15, 0.075),
                                  transforms.RandomGrayscale(),
                                  # transforms.RandomRotation(20),
                                  FixedRotation([0, 90, 180, 270]),
                                  transforms.RandomCrop(384),
                                  transforms.ToTensor(),
                                  normalize,
                              ]))

    # 验证集图片变换
    val_data = ValDataset(val_data_list,
                          transform=transforms.Compose([
                              transforms.Resize((400, 400)),
                              transforms.CenterCrop(384),
                              transforms.ToTensor(),
                              normalize,
                          ]))

    # 测试集图片变换
    test_data = TestDataset(test_data_list,
                            transform=transforms.Compose([
                                transforms.Resize((400, 400)),
                                transforms.CenterCrop(384),
                                transforms.ToTensor(),
                                normalize,
                            ]))

    # 生成图片迭代器
    train_loader = DataLoader(train_data, batch_size=batch_size, shuffle=True, pin_memory=True, num_workers=workers)
    val_loader = DataLoader(val_data, batch_size=batch_size*2, shuffle=False, pin_memory=False, num_workers=workers)
    test_loader = DataLoader(test_data, batch_size=batch_size*2, shuffle=False, pin_memory=False, num_workers=workers)

    # 使用交叉熵损失函数
    criterion = nn.CrossEntropyLoss().cuda()

    # 优化器，使用带amsgrad的Adam
    optimizer = optim.Adam(model.parameters(), lr, weight_decay=weight_decay, amsgrad=True)

    if evaluate:
        validate(val_loader, model, criterion)
    else:
        # 开始训练
        for epoch in range(start_epoch, total_epochs):
            # train for one epoch
            train(train_loader, model, criterion, optimizer, epoch)
            # evaluate on validation set
            precision, avg_loss = validate(val_loader, model, criterion)

            # 在日志文件中记录每个epoch的精度和loss
            with open('./result/%s.txt' % file_name, 'a') as acc_file:
                acc_file.write('Epoch: %2d, Precision: %.8f, Loss: %.8f\n' % (epoch, precision, avg_loss))

            # 记录最高精度与最低loss，保存最新模型与最佳模型
            is_best = precision > best_precision
            is_lowest_loss = avg_loss < lowest_loss
            best_precision = max(precision, best_precision)
            lowest_loss = min(avg_loss, lowest_loss)
            state = {
                'epoch': epoch,
                'state_dict': model.state_dict(),
                'best_precision': best_precision,
                'lowest_loss': lowest_loss,
                'stage': stage,
                'lr': lr,
            }
            save_checkpoint(state, is_best, is_lowest_loss)

            # 判断是否进行下一个stage
            if (epoch + 1) in np.cumsum(stage_epochs)[:-1]:
                stage += 1
                optimizer = adjust_learning_rate()
                model.load_state_dict(torch.load('./model/%s/model_best.pth.tar' % file_name)['state_dict'])
                print('Step into next stage')
                with open('./result/%s.txt' % file_name, 'a') as acc_file:
                    acc_file.write('---------------Step into next stage----------------\n')

    # 记录线下最佳分数
    with open('./result/%s.txt' % file_name, 'a') as acc_file:
        acc_file.write('* best acc: %.8f  %s\n' % (best_precision, os.path.basename(__file__)))
    with open('./result/best_acc.txt', 'a') as acc_file:
        acc_file.write('%s  * best acc: %.8f  %s\n' % (
        time.strftime("%Y-%m-%d %H:%M:%S", time.localtime(time.time())), best_precision, os.path.basename(__file__)))

    # 读取最佳模型，预测测试集，并生成可直接提交的结果文件
    best_model = torch.load('./model/%s/model_best.pth.tar' % file_name)
    model.load_state_dict(best_model['state_dict'])
    test(test_loader=test_loader, model=model)

    # 释放GPU缓存
    torch.cuda.empty_cache()

if __name__ == '__main__':
    main()