# Lion

[Lion (Evolved Sign Momentum)](https://hf.co/papers/2302.06675) is a unique optimizer that uses the sign of the gradient to determine the update direction of the momentum. This makes Lion more memory-efficient and faster than [`AdamW`] which tracks and store the first and second-order moments.

## Lion[[api-class]]

[[autodoc]] bitsandbytes.optim.Lion
    - __init__

## Lion8bit

[[autodoc]] bitsandbytes.optim.Lion8bit
    - __init__

## Lion32bit

[[autodoc]] bitsandbytes.optim.Lion32bit
    - __init__

## PagedLion

[[autodoc]] bitsandbytes.optim.PagedLion
    - __init__

## PagedLion8bit

[[autodoc]] bitsandbytes.optim.PagedLion8bit
    - __init__

## PagedLion32bit

[[autodoc]] bitsandbytes.optim.PagedLion32bit
    - __init__