Pytorch draws train loss and val acc curves

import os
importsys
import json
import torch
import torch.nn as nn
import torch.optim as optim
from torchvision import transforms, datasets
from tqdm import tqdm
from model import resnet34,resnet101
import matplotlib.pyplot as plt
# from csv import readerxon
import numpy as np
from osgeo import gdal
from torchvision.transforms import functional as F
# from torch.utils.tensorboard import SummaryWriter

def main():
    # device = torch.device("cuda:0" if torch.cuda.is_available() else "cpu")
    device = torch.device("cpu")
    # device = torch.device("cuda:0")
    print("using {} device.".format(device))

    data_transform = {
        "train": transforms.Compose([transforms.RandomResizedCrop(224),
                                     transforms.RandomHorizontalFlip(),
                                     transforms.ToTensor(),
                                     transforms.Normalize([0.3971, 0.4091, 0.3681], [0.2169, 0.1943, 0.1917])]),
        "val": transforms.Compose([transforms.Resize(256),
                                   transforms.CenterCrop(224),
                                   transforms.ToTensor(),
                                   transforms.Normalize([0.3971, 0.4091, 0.3681], [0.2169, 0.1943, 0.1917])]),
        "test": transforms.Compose([transforms.RandomResizedCrop(224),
                                     transforms.RandomHorizontalFlip(),
                                     transforms.ToTensor(),
                                     transforms.Normalize([0.3971, 0.4091, 0.3681], [0.2169, 0.1943, 0.1917])]),
    }


    data_root = os.path.abspath(os.path.join(os.getcwd(), "G:/splitdata")) # get data root path
    image_path = os.path.join(data_root, "data") # data set path
    assert os.path.exists(image_path), "{} path does not exist.".format(image_path)
    train_dataset = datasets.ImageFolder(root=os.path.join(image_path, "train"),
                                         transform=data_transform["train"])
    train_num = len(train_dataset)

    flower_list = train_dataset.class_to_idx
    cla_dict = dict((val, key) for key, val in flower_list.items())
    # write dict into json file
    json_str = json.dumps(cla_dict, indent=4)
    with open('class_indices.json', 'w') as json_file:
        json_file.write(json_str)

    batch_size = 16
    nw = min([os.cpu_count(), batch_size if batch_size > 1 else 0, 8]) # number of workers
    print('Using {} dataloader workers every process'.format(nw))

    train_loader = torch.utils.data.DataLoader(train_dataset,
                                               batch_size=batch_size, shuffle=True,
                                               num_workers=nw)

    validate_dataset = datasets.ImageFolder(root=os.path.join(image_path, "val"),
                                            transform=data_transform["val"])
    val_num = len(validate_dataset)
    validate_loader = torch.utils.data.DataLoader(validate_dataset,
                                                  batch_size=batch_size, shuffle=False,
                                                  num_workers=nw)

    test_dataset = datasets.ImageFolder(root=os.path.join(image_path, "test"),
                                            transform=data_transform["test"])
    test_num = len(test_dataset)
    test_loader = torch.utils.data.DataLoader(train_dataset,
                                                  batch_size=batch_size, shuffle=False,
                                                  num_workers=nw)

    print("using {} images for training, {} images for validation, {} images for testing".format(train_num, val_num,
                                                                                                 test_num))

    arry_train = []
    arry_test = []

    def plot_loss(arry_train):
        line1, = plt.plot(range(0, len(arry_train)), arry_train, 'r.-')
        plt_title = 'BATCH_SIZE = 16; EPOCH = 5'
        plt.title(plt_title)
        plt.legend(handles=[line1], labels=["train_loss", "test_loss"], loc="upper right", fontsize=7)
        plt.ylabel('LOSS')
        plt.show()

    # net = ResNet34(classes_num=10)
    net = resnet34()
    model_weight_path = "./resnet34-333f7ec4.pth"
    assert os.path.exists(model_weight_path), "file {} does not exist.".format(model_weight_path)
    net.load_state_dict(torch.load(model_weight_path, map_location='cpu'))

    for param in net.parameters():
        param.requires_grad = False

    in_channel = net.fc.in_features
    net.fc = nn.Linear(in_channel, 30)
    net.to(device)

    #define loss function
    loss_function = nn.CrossEntropyLoss()

    # construct an optimizer
    params = [p for p in net.parameters() if p.requires_grad]
    optimizer = optim.Adam(params, lr=0.001)



    epochs = 20
    best_acc = 0.0
    save_path = './best.pth'
    train_steps = len(train_loader)
    total_test_step = 0

    Loss_list = []
    Accuracy_list = []

    for epoch in range(epochs):
        #train
        net.train()
        running_loss = 0.0
        train_bar = tqdm(train_loader, file=sys.stdout)
        for step, data in enumerate(train_bar):
            images, labels = data
            optimizer.zero_grad()
            logits = net(images.to(device))
            loss = loss_function(logits, labels.to(device))
            loss.backward()
            optimizer.step()

            # print statistics
            running_loss + = loss.item()

            arry_train.append(loss)

            train_bar.desc = "train epoch[{}/{}] loss:{:.3f}".format(epoch + 1,
                                                                     epochs,
                                                                     loss)



        #validate
        net.eval()
        acc = 0.0 #accumulate accurate number / epoch
        with torch.no_grad():
            val_bar = tqdm(validate_loader, file=sys.stdout)
            for val_data in val_bar:
                val_images, val_labels = val_data
                outputs = net(val_images.to(device))
                # loss = loss_function(outputs, test_labels)
                predict_y = torch.max(outputs, dim=1)[1]
                acc + = torch.eq(predict_y, val_labels.to(device)).sum().item()

                val_bar.desc = "valid epoch[{}/{}]".format(epoch + 1,
                                                           epochs)

        val_accurate = acc / val_num
        print('[epoch %d] train_loss: %.3f val_accuracy: %.3f' %
              (epoch + 1, running_loss / train_steps, val_accurate))

        Loss_list.append(running_loss / train_steps)
        Accuracy_list.append(val_accurate)


        if val_accurate > best_acc:
            best_acc = val_accurate
            torch.save(net.state_dict(), save_path)

    print('Finished')

    x1 = range(0, 10)
    x2 = range(0, 10)
    y1 = Accuracy_list
    y2 = Loss_list
    plt.subplot(2, 1, 1)
    plt.plot(x1, y1, 'o-')
    plt.title('val accuracy')
    plt.ylabel('val accuracy')
    plt.subplot(2, 1, 2)
    plt.plot(x2, y2, '.-')
    plt.xlabel('training loss')
    plt.ylabel('training')
    plt.show()
    plt.savefig("accuracy_loss.jpg")


if __name__ == '__main__':
    main()