人工智能技术 lab4(MNIST手写数字识别)

source code and requirements

0.实验环境

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OS: Arch Linux(rolling)
LANG: Python 3.11.5

4.运行

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python another_lab4/main.py

another_lab4/main.py

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import torch
from torch.utils.data import DataLoader
from torchvision import transforms
from torchvision.datasets import MNIST
import matplotlib.pyplot as plt


class Net(torch.nn.Module):

def __init__(self):
super().__init__()
self.fc1 = torch.nn.Linear(28*28, 64)
self.fc2 = torch.nn.Linear(64, 64)
self.fc3 = torch.nn.Linear(64, 64)
self.fc4 = torch.nn.Linear(64, 10)

def forward(self, x):
x = torch.nn.functional.relu(self.fc1(x))
x = torch.nn.functional.relu(self.fc2(x))
x = torch.nn.functional.relu(self.fc3(x))
x = torch.nn.functional.log_softmax(self.fc4(x), dim=1)
return x


def get_data_loader(is_train):
to_tensor = transforms.Compose([transforms.ToTensor()])
data_set = MNIST("", is_train, transform=to_tensor, download=True)
return DataLoader(data_set, batch_size=15, shuffle=True)


def evaluate(test_data, net):
n_correct = 0
n_total = 0
with torch.no_grad():
for (x, y) in test_data:
outputs = net.forward(x.view(-1, 28*28))
for i, output in enumerate(outputs):
if torch.argmax(output) == y[i]:
n_correct += 1
n_total += 1
return n_correct / n_total


def main():

train_data = get_data_loader(is_train=True)
test_data = get_data_loader(is_train=False)
net = Net()

print("initial accuracy:", evaluate(test_data, net))
optimizer = torch.optim.Adam(net.parameters(), lr=0.001)
for epoch in range(2):
for (x, y) in train_data:
net.zero_grad()
output = net.forward(x.view(-1, 28*28))
loss = torch.nn.functional.nll_loss(output, y)
loss.backward()
optimizer.step()
print("epoch", epoch, "accuracy:", evaluate(test_data, net))

for (n, (x, _)) in enumerate(test_data):
if n > 3:
break
predict = torch.argmax(net.forward(x[0].view(-1, 28*28)))
plt.figure(n)
plt.imshow(x[0].view(28, 28))
plt.title("prediction: " + str(int(predict)))
plt.show()


if __name__ == "__main__":
main()

5.实验结果


人工智能技术 lab4(MNIST手写数字识别)
https://lilinzta.github.io/2023/11/26/人工智能技术-lab4-MNIST手写数字识别/
作者
Haotian Li
发布于
2023年11月26日
许可协议