Practical 6
Machine Learning, spring 2015
In this practical, we train an LSTM for character-level language modelling. Since this is the last week for practicals, it will be extremely short and does not require writing code, and is due by the end of the Friday's session (regardless of whether you are from the Wednesday or Friday session).
See PDF for details.
Setup
Setup will be the same as last time in practical 1. Please refer to the practical 1 repository, and run the script as instructed last time. If you get an error that nngraph is not installed, run:
luarocks install nngraph
Do this before reading the pdf
Clone the practical and download the associated data:
git clone https://github.com/oxford-cs-ml-2015/practical6.git
cd practical6
wget http://www.cs.ox.ac.uk/people/brendan.shillingford/teaching/practical6-data.tar.gz
tar xvf practical6-data.tar.gz
and start training the model:
th train.lua -vocabfile vocab.t7 -datafile train.t7
Make note of the time at which you run the train.lua script. Every several iterations, the training script will save the current model (including its parameters) to a file called model_autosave.t7. You can make snapshots of this file if you want, but this is not required for the practical.
For users outside of Oxford's CS lab
The practical6-data.tar.gz file is for 64-bit little-endian CPUs. For all other machines (i.e. if running uname -m doesn't print out x86_64), then see this comment for instructions:
https://github.com/oxford-cs-ml-2015/practical6/commit/96749c8d9bc93f864c94c048a3c8cd73f59f733b#commitcomment-11003337. This is the same data, but using ASCII serialization.
You may also want to use this faster LSTM factory method, instead of the one in this repository: https://gist.github.com/karpathy/7bae8033dcf5ca2630ba which performs all the matrix multiplications at once followed by several nn.Narrow operations to extract out the gate values; read its comments for details.
See course page for practicals
https://www.cs.ox.ac.uk/people/nando.defreitas/machinelearning/