Unlike from the previous PaddlePaddle v2, in the new API (Fluid), we do not need to calculate word embedding ourselves. PaddlePaddle provides a built-in method `fluid.layers.embedding` and we can use it directly to build our N-gram neural network model.
- We define our N-gram neural network structure as below. This structure will be used both in `train` and in `infer`
- We define our N-gram neural network structure as below. This structure will be used both in `train` and in `infer`. We can specify `is_sparse = True` to accelerate sparse matrix update for word embedding.