Libtorch: cannot load traced lstm scriptmodel

Question

I save a pytorch ScriptModule and load it using libtorch. However I encountered the following problem

I use linux subsystem under win10 and I use pytorch 1.2.

To reproduce my problem, you could run this piece of python code to save a pt model

import torch
import torch.nn as nn


# TODO: https://github.com/pytorch/pytorch/issues/23930
class test(torch.jit.ScriptModule):

    def __init__(self, vocab_size=10, rnn_dims=512):
        super().__init__()
        self.word_embeds = nn.Embedding(vocab_size, rnn_dims)
        self.emb_drop = nn.Dropout(0.1)
        self.rnn = nn.LSTM(input_size=rnn_dims, hidden_size=rnn_dims, batch_first=True,
                           num_layers=2, dropout=0.1)
        # delattr(self.rnn, 'forward_packed')

    @torch.jit.script_method
    def forward(self, x):
        h1 = (torch.zeros(2, 1, 512), torch.zeros(2, 1, 512))
        embeds = self.emb_drop(self.word_embeds(x))
        out, h1 = self.rnn(embeds, h1)

        return h1


model = test()

input = torch.ones((1,3)).long()
output = model(input)
print('output', output)

# torch.onnx.export(model,  # model being run
#                   input,
#                   'test.onnx',
#                   example_outputs=output)
#torch.jit.trace(model, (torch.ones((1,3)).long(), torch.ones((3,1))), check_trace=False)
model.save('lstm_test.pt')

Then load the model in libtorch.

I don't know why I have this error. I don't use PackedSequence at all. Hope some could help me out.

Answer 1

I know what's wrong now. The libtorch version is of wrong version on the official website. It's ok now when I use the correct libtorch 1.2. Refer to issue https://github.com/pytorch/pytorch/issues/24382