示例写的挺详细的吧，用全连接层先做线性映射

import paddle.fluid as fluid
emb_dim = 768
vocab_size = 512
hidden_dim = 512    # 自己定

data = fluid.layers.data(name='x', shape=[1], dtype='int32', lod_level=1)
emb = fluid.layers.embedding(input=data, size=[vocab_size, emb_dim], is_sparse=True)

forward_proj = fluid.layers.fc(input=emb, size=hidden_dim * 4, bias_attr=False)
forward, cell = fluid.layers.dynamic_lstm(input=forward_proj, size=hidden_dim * 4, use_peepholes=False)
forward.shape  # (-1, 512)
cell.shape  # (-1, 512)