Fix tokenization edge case where llama output does not start with a space#1375
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Fixing to compare to b' ' instead of (str)' '
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Is it possible to review this? I think its a very straightforward fix. |
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@noamgat yup and thank you for looking into this |
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Created following investigation in this issue:
noamgat/lm-format-enforcer#92
See this notebook for a reproduction of the problem:
https://colab.research.google.com/drive/1Ooz11nFPk19zyJdMDx42CeesU8aWZMdI#scrollTo=oKpHw5PZ30uC
When using the model
TheBloke/tinyllama-1.1b-chat-v1.0-GGUFIn the current implementation, the token sequence
[6377]decodes to{"while the token sequence[1,6377]decodes to". This is because the LLama tokenizer doesn't add a leading space when decoding this sequence, but the llama-cpp-python code that wraps it assumes that it does.This breaks that assumption, and only returns
output[1:]instead ofoutputwhen the first character is a space.Implementation note: I made the check
output[0:1] == ' 'and notoutput[0] == ' 'to avoid edge cases where the output is empty (maybe if the first tokens are partial unicode characters).