Created by: wanghaoshuang

forward_program = fluid.Program()
loss = None
with fluid.program_guad(main_program=forward_program):
    input = fluid.layers.data(name="input")
    label = fluid.layers.data(name="label")
    out = fluid.layers.fc(input, size=10)
    loss = fluid.layers.cross_entropy(out, label)

for epoch in range(10):
    if epoch > 5:
        lr = 0.01
    train_program = forward_program.clone()
    with fluid.program_guad(main_program=train_program):
        loss = train_program.global_block().get_var(loss.name)
        optimizer = fluid.layers.Adam(learning_rate=lr)
        optimizer.minimize(loss)

    exe.run(train_program)