作业二完整代码如下

# Import需要的套件
import os
import numpy as np
import cv2
import torch
import torch.nn as nn
import torchvision.transforms as transforms
import pandas as pd
from torch.utils.data import DataLoader, Dataset
import time

#Read image 利用 OpenCV (cv2) 讀入照片並存放在 numpy array 中
def readfile(path, label):
# label 是一個 boolean variable，代表需不需要回傳 y 值
image_dir = sorted(os.listdir(path))
x = np.zeros((len(image_dir), 128, 128, 3), dtype=np.uint8)
y = np.zeros((len(image_dir)), dtype=np.uint8)
for i, file in enumerate(image_dir):
img = cv2.imread(os.path.join(path, file))
x[i, :, :] = cv2.resize(img,(128, 128))
if label:
y[i] = int(file.split("_")[0])
if label:
return x, y
else:
return x

# 分別將 training set、validation set、testing set 用 readfile 函式讀進來
workspace_dir = './food-11'
print("Reading data")
train_x, train_y = readfile(os.path.join(workspace_dir, "training"), True)
print("Size of training data = {}".format(len(train_x)))
val_x, val_y = readfile(os.path.join(workspace_dir, "validation"), True)
print("Size of validation data = {}".format(len(val_x)))
test_x = readfile(os.path.join(workspace_dir, "testing"), False)
print("Size of Testing data = {}".format(len(test_x)))

# training 時做 data augmentation
train_transform = transforms.Compose([
transforms.ToPILImage(),
transforms.RandomHorizontalFlip(), # 隨機將圖片水平翻轉
transforms.RandomRotation(15), # 隨機旋轉圖片
transforms.ToTensor(), # 將圖片轉成 Tensor，並把數值 normalize 到 [0,1] (data normalization)
])
# testing 時不需做 data augmentation
test_transform = transforms.Compose([
transforms.ToPILImage(),
transforms.ToTensor(),
])
class ImgDataset(Dataset):
def __init__(self, x, y=None, transform=None):
self.x = x
# label is required to be a LongTensor
self.y = y
if y is not None:
self.y = torch.LongTensor(y)
self.transform = transform
def __len__(self):
return len(self.x)
def __getitem__(self, index):
X = self.x[index]
if self.transform is not None:
X = self.transform(X)
if self.y is not None:
Y = self.y[index]
return X, Y
else:
return X

batch_size = 64
train_set = ImgDataset(train_x, train_y, train_transform)
val_set = ImgDataset(val_x, val_y, test_transform)
train_loader = DataLoader(train_set, batch_size=batch_size, shuffle=True)
val_loader = DataLoader(val_set, batch_size=batch_size, shuffle=False)

class Classifier(nn.Module):
def __init__(self):
super(Classifier, self).__init__()
# torch.nn.Conv2d(in_channels, out_channels, kernel_size, stride, padding)
# torch.nn.MaxPool2d(kernel_size, stride, padding)
# input 維度 [3, 128, 128]
self.cnn = nn.Sequential(
nn.Conv2d(3, 64, 3, 1, 1), # [64, 128, 128]
nn.BatchNorm2d(64),
nn.ReLU(),
nn.MaxPool2d(2, 2, 0), # [64, 64, 64]

nn.Conv2d(64, 128, 3, 1, 1), # [128, 64, 64]
nn.BatchNorm2d(128),
nn.ReLU(),
nn.MaxPool2d(2, 2, 0), # [128, 32, 32]

nn.Conv2d(128, 256, 3, 1, 1), # [256, 32, 32]
nn.BatchNorm2d(256),
nn.ReLU(),
nn.MaxPool2d(2, 2, 0), # [256, 16, 16]

nn.Conv2d(256, 512, 3, 1, 1), # [512, 16, 16]
nn.BatchNorm2d(512),
nn.ReLU(),
nn.MaxPool2d(2, 2, 0), # [512, 8, 8]

nn.Conv2d(512, 512, 3, 1, 1), # [512, 8, 8]
nn.BatchNorm2d(512),
nn.ReLU(),
nn.MaxPool2d(2, 2, 0), # [512, 4, 4]
)
self.fc = nn.Sequential(
nn.Linear(512 * 4 * 4, 1024),
nn.ReLU(),
nn.Linear(1024, 512),
nn.ReLU(),
nn.Linear(512, 11)
)

def forward(self, x):
out = self.cnn(x)
out = out.view(out.size()[0], -1)
return self.fc(out)

model = Classifier().cuda()
loss = nn.CrossEntropyLoss() # 因為是 classification task，所以 loss 使用 CrossEntropyLoss
optimizer = torch.optim.Adam(model.parameters(), lr=0.001) # optimizer 使用 Adam
num_epoch = 30

for epoch in range(num_epoch):
epoch_start_time = time.time()
train_acc = 0.0
train_loss = 0.0
val_acc = 0.0
val_loss = 0.0

model.train() # 確保 model 是在 train model (開啟 Dropout 等...)
for i, data in enumerate(train_loader):
optimizer.zero_grad() # 用 optimizer 將 model 參數的 gradient 歸零
train_pred = model(data[0].cuda()) # 利用 model 得到預測的機率分佈 這邊實際上就是去呼叫 model 的 forward 函數
batch_loss = loss(train_pred, data[1].cuda()) # 計算 loss （注意 prediction 跟 label 必須同時在 CPU 或是 GPU 上）
batch_loss.backward() # 利用 back propagation 算出每個參數的 gradient
optimizer.step() # 以 optimizer 用 gradient 更新參數值

train_acc += np.sum(np.argmax(train_pred.cpu().data.numpy(), axis=1) == data[1].numpy())
train_loss += batch_loss.item()

model.eval()
with torch.no_grad():
for i, data in enumerate(val_loader):
val_pred = model(data[0].cuda())
batch_loss = loss(val_pred, data[1].cuda())

val_acc += np.sum(np.argmax(val_pred.cpu().data.numpy(), axis=1) == data[1].numpy())
val_loss += batch_loss.item()

# 將結果 print 出來
print('[%03d/%03d] %2.2f sec(s) Train Acc: %3.6f Loss: %3.6f | Val Acc: %3.6f loss: %3.6f' % \
(epoch + 1, num_epoch, time.time() - epoch_start_time, \
train_acc / train_set.__len__(), train_loss / train_set.__len__(), val_acc / val_set.__len__(),
val_loss / val_set.__len__()))

train_val_x = np.concatenate((train_x, val_x), axis=0)
train_val_y = np.concatenate((train_y, val_y), axis=0)
train_val_set = ImgDataset(train_val_x, train_val_y, train_transform)
train_val_loader = DataLoader(train_val_set, batch_size=batch_size, shuffle=True)

model_best = Classifier().cuda()
loss = nn.CrossEntropyLoss() # 因為是 classification task，所以 loss 使用 CrossEntropyLoss
optimizer = torch.optim.Adam(model_best.parameters(), lr=0.001) # optimizer 使用 Adam
num_epoch = 30

for epoch in range(num_epoch):
epoch_start_time = time.time()
train_acc = 0.0
train_loss = 0.0

model_best.train()
for i, data in enumerate(train_val_loader):
optimizer.zero_grad()
train_pred = model_best(data[0].cuda())
batch_loss = loss(train_pred, data[1].cuda())
batch_loss.backward()
optimizer.step()

train_acc += np.sum(np.argmax(train_pred.cpu().data.numpy(), axis=1) == data[1].numpy())
train_loss += batch_loss.item()

#將結果 print 出來
print('[%03d/%03d] %2.2f sec(s) Train Acc: %3.6f Loss: %3.6f' % \
(epoch + 1, num_epoch, time.time()-epoch_start_time, \
train_acc/train_val_set.__len__(), train_loss/train_val_set.__len__()))

test_set = ImgDataset(test_x, transform=test_transform)
test_loader = DataLoader(test_set, batch_size=batch_size, shuffle=False)
model_best.eval()
prediction = []
with torch.no_grad():
for i, data in enumerate(test_loader):
test_pred = model_best(data.cuda())
test_label = np.argmax(test_pred.cpu().data.numpy(), axis=1)
for y in test_label:
prediction.append(y)
#將結果寫入 csv 檔
with open("predict.csv", 'w') as f:
f.write('Id,Category\n')
for i, y in enumerate(prediction):
f.write('{},{}\n'.format(i, y))