fix a bug in beam_search (moving log_softmax after logits_processor)
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Fix a bug in beam_search function. If we use `log_softmax` before `logits_processor`, then the processed logits may not represent logP correctly because some logits may be set to `-inf` while other logits remain unchanged (i.e., `sum(exp(logits))!=1)`. This can significantly influence the generation results in my cases.

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_The documentation is not available anymore as the PR was closed or merged._<|||||>This issue has been automatically marked as stale because it has not had recent activity. If you think this still needs to be addressed please comment on this thread.

Please note that issues that do not follow the [contributing guidelines](https://github.com/huggingface/transformers/blob/main/CONTRIBUTING.md) are likely to be ignored.<|||||>Maybe of interest to @gante ?<|||||>Hey @nonstopfor 👋 

Yes, your point is correct -- the normalization should happen after the logits processors. We have a flag to do it -- if you call `generate` with `renormalize_logits=True`, the last logit processor renormalizes your logits :)

This means this PR should not be needed -- let me know if it doesn't address your problem.<|||||>Ok. Thanks.