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multifit/fastai_contrib/models.py
T

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1.9 KiB
Python

from fastai.torch_core import *
from fastai.layers import *
from fastai.text.models import *
class BiLMModel(nn.Module):
def __init__(self, fwd_lm:nn.Module, bwd_lm:nn.Module):
super().__init__()
self.fwd_lm = fwd_lm
self.bwd_lm = bwd_lm
def forward(self, input):
sl, bs, tracks = input.size()
decoded = []
raw_outputs = []
outputs = []
fwd_o = self.fwd_lm(input[..., 0])
bwd_o = self.bwd_lm(input[..., 1])
return torch.stack([fwd_o[0], bwd_o[0]], dim=2), (fwd_o[1]+bwd_o[1]), (fwd_o[2] + bwd_o[2])
def reset(self):
"Reset the hidden states of underlaying lms."
self.fwd_lm.reset()
self.bwd_lm.reset()
def get_bilm(vocab_sz:int, emb_sz:int, n_hid:int, n_layers:int, pad_token:int, tie_weights:bool=True,
qrnn:bool=False, bias:bool=True, bidir:bool=False, output_p:float=0.4, hidden_p:float=0.2, input_p:float=0.6,
embed_p:float=0.1, weight_p:float=0.5)->nn.Module:
"Create a two AWD-LSTM one for each direction "
fwd_rnn_enc = RNNCore(vocab_sz, emb_sz, n_hid=n_hid, n_layers=n_layers, pad_token=pad_token, qrnn=qrnn, bidir=bidir,
hidden_p=hidden_p, input_p=input_p, embed_p=embed_p, weight_p=weight_p)
bwd_rnn_enc = RNNCore(vocab_sz, emb_sz, n_hid=n_hid, n_layers=n_layers, pad_token=pad_token, qrnn=qrnn, bidir=bidir,
hidden_p=hidden_p, input_p=input_p, embed_p=embed_p, weight_p=weight_p)
enc = None
if tie_weights:
enc = fwd_rnn_enc.encoder
fwd_rnn_enc.encoder.weight = enc.weight
bwd_rnn_enc.encoder.weight = enc.weight
return BiLMModel(
fwd_lm=SequentialRNN(fwd_rnn_enc, LinearDecoder(vocab_sz, emb_sz, output_p, tie_encoder=enc, bias=bias)),
bwd_lm=SequentialRNN(bwd_rnn_enc, LinearDecoder(vocab_sz, emb_sz, output_p, tie_encoder=enc, bias=bias)))