Request support for Eleuther generative task

[ScottHoang]

Hi all,
Thank you for the excellent work you guys have been doing thus far.
I request that we add support to Eleuther's generative tasks.
We are not encoding batch prompts correctly, leading to an index lookup error in tok_embeddings.
Can you help?
Thank you!

[kartikayk]

Thanks so much for opening this issue. Coincidently @joecummings is working on this right now.

[joecummings]

@ScottHoang This was enabled in #975 - check it out!

[ebsmothers]

@joecummings this should be completed, right? Gonna close the issue but re-open if I'm mistaken here