Need modification to be compatible with pytorch v0.4

[kan-bayashi]

Hi all,

Pytorch is updated to version 0.4.
It requires some change to migrate from 0.3.1 to 0.4.
See detail from following url.
http://pytorch.org/2018/04/22/0_4_0-migration-guide.html

[sw005320]

This actually causes a problem when we install warp_ctc. @ShigekiKarita, can you fix it?
Easy solution is

pytorch: venv/bin/activate
        . venv/bin/activate && conda install pytorch==0.3.1 -c pytorch

[Peidong-Wang]

Is upgrading to 0.4.0 a desired change? It may lose the compatibility to earlier versions of pytorch. @kan-bayashi

[kan-bayashi]

@pozhijisi It's not desired change, but we have to move on pytorch v0.4 sooner or later due to the development of new functions.

[sw005320]

@arendu may comment about this. We had discussions about this today.

[arendu-zz]

pytorch 4 has some significant changes compared to 3... maybe best to update after the workshop?