本文实例讲述了Python使用gluon/mxnet模块实现的mnist手写数字识别功能。分享给大家供大家参考，具体如下：
import gluonbook as gb
from mxnet import autograd,nd,init,gluon
from mxnet.gluon import loss as gloss,data as gdata,nn,utils as gutils
import mxnet as mx
net = nn.Sequential()
with net.name_scope():
net.add(
nn.Conv2D(channels=32, kernel_size=5, activation='relu'),
nn.MaxPool2D(pool_size=2, strides=2),
nn.Flatten(),
nn.Dense(128, activation='sigmoid'),
nn.Dense(10, activation='sigmoid')
)
lr = 0.5
batch_size=256
ctx = mx.gpu()
net.initialize(init=init.Xavier(), ctx=ctx)
train_data, test_data = gb.load_data_fashion_mnist(batch_size)
trainer = gluon.Trainer(net.collect_params(),'sgd',{'learning_rate' : lr})
loss = gloss.SoftmaxCrossEntropyLoss()
num_epochs = 30
def train(train_data, test_data, net, loss, trainer,num_epochs):
for epoch in range(num_epochs):
total_loss = 0
for x,y in train_data:
with autograd.record():
x = x.as_in_context(ctx)
y = y.as_in_context(ctx)
y_hat=net(x)
l = loss(y_hat,y)
l.backward()
total_loss += l
trainer.step(batch_size)
mx.nd.waitall()
print("Epoch [{}]: Loss {}".format(epoch, total_loss.sum().asnumpy()[0]/(batch_size*len(train_data))))
if __name__ == '__main__':
try:
ctx = mx.gpu()
_ = nd.zeros((1,), ctx=ctx)
except:
ctx = mx.cpu()
ctx
gb.train(train_data,test_data,net,loss,trainer,ctx,num_epochs)
更多关于Python相关内容可查看本站专题：《Python数学运算技巧总结》、《Python图片操作技巧总结》、《Python数据结构与算法教程》、《Python函数使用技巧总结》、《Python字符串操作技巧汇总》及《Python入门与进阶经典教程》
希望本文所述对大家Python程序设计有所帮助。
