Frequently Asked Questions

This document contains a number of questions that are regularly asked on GitHub Issues.

Why is my model not generating a response?

For a generative model, check that --skip-generation is set to False.

Why can’t I reproduce the results of an evaluation on a task with a pretrained model?

One common culprit for this is that the flags for that task may not be correctly set. When loading a pretrained checkpoint, all of the parameters for the model itself will be loaded from the model’s .opt file, but all task-specific parameters will need to be re-specified.

Why is my generative model’s perplexity so high (>1000) when evaluating?

One first thing to check is whether there is a problem with your dictionary or token embeddings, because this high perplexity implies that the model is very bad at predicting the next token in a string of text.

I changed my teacher and now its tests won’t pass.

Take a careful look at the diff outputs that those tests produce. If the results look expected, then you can update the regression fixtures (stored, expected results) with:

pytest --force-regen parlai/tasks/TASK_NAME_HERE/