第五天、训练神经网络

准备工作

要进行PaddlePaddle Fluid单机训练，需要先 准备数据 和 配置简单的网络 。当配置简单的网络 完毕后，可以得到两个fluid.Program， startup_program 和 main_program。 默认情况下，可以使用 fluid.default_startup_program()与fluid.default_main_program() 获得全局的 fluid.Program。

import paddle.fluid as fluid

image = fluid.layers.data(name="image", shape=[784])
label = fluid.layers.data(name="label", shape=[1])
hidden = fluid.layers.fc(input=image, size=100, act='relu')
prediction = fluid.layers.fc(input=hidden, size=10, act='softmax')
loss = fluid.layers.cross_entropy(input=prediction, label=label)
loss = fluid.layers.mean(loss)

sgd = fluid.optimizer.SGD(learning_rate=0.001)
sgd.minimize(loss)

# Here the fluid.default_startup_program() and fluid.default_main_program()
# has been constructed