bitsandbytes/main/en/reference/optim/lion.md

# 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]][[bitsandbytes.optim.Lion]]

#### bitsandbytes.optim.Lion[[bitsandbytes.optim.Lion]]

[Source](https://github.com/bitsandbytes-foundation/bitsandbytes/blob/main/bitsandbytes/optim/lion.py#L8)

__init__bitsandbytes.optim.Lion.__init__https://github.com/bitsandbytes-foundation/bitsandbytes/blob/main/bitsandbytes/optim/lion.py#L9[{"name": "params", "val": ""}, {"name": "lr", "val": " = 0.0001"}, {"name": "betas", "val": " = (0.9, 0.99)"}, {"name": "weight_decay", "val": " = 0"}, {"name": "optim_bits", "val": " = 32"}, {"name": "args", "val": " = None"}, {"name": "min_8bit_size", "val": " = 4096"}, {"name": "is_paged", "val": " = False"}]- **params** (`torch.tensor`) --
  The input parameters to optimize.
- **lr** (`float`, defaults to 1e-4) --
  The learning rate.
- **betas** (`tuple(float, float)`, defaults to (0.9, 0.999)) --
  The beta values are the decay rates of the first and second-order moment of the optimizer.
- **weight_decay** (`float`, defaults to 0) --
  The weight decay value for the optimizer.
- **optim_bits** (`int`, defaults to 32) --
  The number of bits of the optimizer state.
- **args** (`object`, defaults to `None`) --
  An object with additional arguments.
- **min_8bit_size** (`int`, defaults to 4096) --
  The minimum number of elements of the parameter tensors for 8-bit optimization.
- **is_paged** (`bool`, defaults to `False`) --
  Whether the optimizer is a paged optimizer or not.0

Base Lion optimizer.

**Parameters:**

params (`torch.tensor`) : The input parameters to optimize.

lr (`float`, defaults to 1e-4) : The learning rate.

betas (`tuple(float, float)`, defaults to (0.9, 0.999)) : The beta values are the decay rates of the first and second-order moment of the optimizer.

weight_decay (`float`, defaults to 0) : The weight decay value for the optimizer.

optim_bits (`int`, defaults to 32) : The number of bits of the optimizer state.

args (`object`, defaults to `None`) : An object with additional arguments.

min_8bit_size (`int`, defaults to 4096) : The minimum number of elements of the parameter tensors for 8-bit optimization.

is_paged (`bool`, defaults to `False`) : Whether the optimizer is a paged optimizer or not.

## Lion8bit[[bitsandbytes.optim.Lion8bit]]

#### bitsandbytes.optim.Lion8bit[[bitsandbytes.optim.Lion8bit]]

[Source](https://github.com/bitsandbytes-foundation/bitsandbytes/blob/main/bitsandbytes/optim/lion.py#L55)

__init__bitsandbytes.optim.Lion8bit.__init__https://github.com/bitsandbytes-foundation/bitsandbytes/blob/main/bitsandbytes/optim/lion.py#L56[{"name": "params", "val": ""}, {"name": "lr", "val": " = 0.0001"}, {"name": "betas", "val": " = (0.9, 0.99)"}, {"name": "weight_decay", "val": " = 0"}, {"name": "args", "val": " = None"}, {"name": "min_8bit_size", "val": " = 4096"}, {"name": "is_paged", "val": " = False"}]- **params** (`torch.tensor`) --
  The input parameters to optimize.
- **lr** (`float`, defaults to 1e-4) --
  The learning rate.
- **betas** (`tuple(float, float)`, defaults to (0.9, 0.999)) --
  The beta values are the decay rates of the first and second-order moment of the optimizer.
- **weight_decay** (`float`, defaults to 0) --
  The weight decay value for the optimizer.
- **args** (`object`, defaults to `None`) --
  An object with additional arguments.
- **min_8bit_size** (`int`, defaults to 4096) --
  The minimum number of elements of the parameter tensors for 8-bit optimization.
- **is_paged** (`bool`, defaults to `False`) --
  Whether the optimizer is a paged optimizer or not.0

8-bit Lion optimizer.

**Parameters:**

params (`torch.tensor`) : The input parameters to optimize.

lr (`float`, defaults to 1e-4) : The learning rate.

betas (`tuple(float, float)`, defaults to (0.9, 0.999)) : The beta values are the decay rates of the first and second-order moment of the optimizer.

weight_decay (`float`, defaults to 0) : The weight decay value for the optimizer.

args (`object`, defaults to `None`) : An object with additional arguments.

min_8bit_size (`int`, defaults to 4096) : The minimum number of elements of the parameter tensors for 8-bit optimization.

is_paged (`bool`, defaults to `False`) : Whether the optimizer is a paged optimizer or not.

## Lion32bit[[bitsandbytes.optim.Lion32bit]]

#### bitsandbytes.optim.Lion32bit[[bitsandbytes.optim.Lion32bit]]

[Source](https://github.com/bitsandbytes-foundation/bitsandbytes/blob/main/bitsandbytes/optim/lion.py#L99)

__init__bitsandbytes.optim.Lion32bit.__init__https://github.com/bitsandbytes-foundation/bitsandbytes/blob/main/bitsandbytes/optim/lion.py#L100[{"name": "params", "val": ""}, {"name": "lr", "val": " = 0.0001"}, {"name": "betas", "val": " = (0.9, 0.99)"}, {"name": "weight_decay", "val": " = 0"}, {"name": "args", "val": " = None"}, {"name": "min_8bit_size", "val": " = 4096"}, {"name": "is_paged", "val": " = False"}]- **params** (`torch.tensor`) --
  The input parameters to optimize.
- **lr** (`float`, defaults to 1e-4) --
  The learning rate.
- **betas** (`tuple(float, float)`, defaults to (0.9, 0.999)) --
  The beta values are the decay rates of the first and second-order moment of the optimizer.
- **weight_decay** (`float`, defaults to 0) --
  The weight decay value for the optimizer.
- **args** (`object`, defaults to `None`) --
  An object with additional arguments.
- **min_8bit_size** (`int`, defaults to 4096) --
  The minimum number of elements of the parameter tensors for 8-bit optimization.
- **is_paged** (`bool`, defaults to `False`) --
  Whether the optimizer is a paged optimizer or not.0

32-bit Lion optimizer.

**Parameters:**

params (`torch.tensor`) : The input parameters to optimize.

lr (`float`, defaults to 1e-4) : The learning rate.

betas (`tuple(float, float)`, defaults to (0.9, 0.999)) : The beta values are the decay rates of the first and second-order moment of the optimizer.

weight_decay (`float`, defaults to 0) : The weight decay value for the optimizer.

args (`object`, defaults to `None`) : An object with additional arguments.

min_8bit_size (`int`, defaults to 4096) : The minimum number of elements of the parameter tensors for 8-bit optimization.

is_paged (`bool`, defaults to `False`) : Whether the optimizer is a paged optimizer or not.

## PagedLion[[bitsandbytes.optim.PagedLion]]

#### bitsandbytes.optim.PagedLion[[bitsandbytes.optim.PagedLion]]

[Source](https://github.com/bitsandbytes-foundation/bitsandbytes/blob/main/bitsandbytes/optim/lion.py#L143)

__init__bitsandbytes.optim.PagedLion.__init__https://github.com/bitsandbytes-foundation/bitsandbytes/blob/main/bitsandbytes/optim/lion.py#L144[{"name": "params", "val": ""}, {"name": "lr", "val": " = 0.0001"}, {"name": "betas", "val": " = (0.9, 0.99)"}, {"name": "weight_decay", "val": " = 0"}, {"name": "optim_bits", "val": " = 32"}, {"name": "args", "val": " = None"}, {"name": "min_8bit_size", "val": " = 4096"}]- **params** (`torch.tensor`) --
  The input parameters to optimize.
- **lr** (`float`, defaults to 1e-4) --
  The learning rate.
- **betas** (`tuple(float, float)`, defaults to (0.9, 0.999)) --
  The beta values are the decay rates of the first and second-order moment of the optimizer.
- **weight_decay** (`float`, defaults to 0) --
  The weight decay value for the optimizer.
- **optim_bits** (`int`, defaults to 32) --
  The number of bits of the optimizer state.
- **args** (`object`, defaults to `None`) --
  An object with additional arguments.
- **min_8bit_size** (`int`, defaults to 4096) --
  The minimum number of elements of the parameter tensors for 8-bit optimization.0

Paged Lion optimizer.

**Parameters:**

params (`torch.tensor`) : The input parameters to optimize.

lr (`float`, defaults to 1e-4) : The learning rate.

betas (`tuple(float, float)`, defaults to (0.9, 0.999)) : The beta values are the decay rates of the first and second-order moment of the optimizer.

weight_decay (`float`, defaults to 0) : The weight decay value for the optimizer.

optim_bits (`int`, defaults to 32) : The number of bits of the optimizer state.

args (`object`, defaults to `None`) : An object with additional arguments.

min_8bit_size (`int`, defaults to 4096) : The minimum number of elements of the parameter tensors for 8-bit optimization.

## PagedLion8bit[[bitsandbytes.optim.PagedLion8bit]]

#### bitsandbytes.optim.PagedLion8bit[[bitsandbytes.optim.PagedLion8bit]]

[Source](https://github.com/bitsandbytes-foundation/bitsandbytes/blob/main/bitsandbytes/optim/lion.py#L187)

__init__bitsandbytes.optim.PagedLion8bit.__init__https://github.com/bitsandbytes-foundation/bitsandbytes/blob/main/bitsandbytes/optim/lion.py#L188[{"name": "params", "val": ""}, {"name": "lr", "val": " = 0.0001"}, {"name": "betas", "val": " = (0.9, 0.99)"}, {"name": "weight_decay", "val": " = 0"}, {"name": "args", "val": " = None"}, {"name": "min_8bit_size", "val": " = 4096"}]- **params** (`torch.tensor`) --
  The input parameters to optimize.
- **lr** (`float`, defaults to 1e-4) --
  The learning rate.
- **betas** (`tuple(float, float)`, defaults to (0.9, 0.999)) --
  The beta values are the decay rates of the first and second-order moment of the optimizer.
- **weight_decay** (`float`, defaults to 0) --
  The weight decay value for the optimizer.
- **args** (`object`, defaults to `None`) --
  An object with additional arguments.
- **min_8bit_size** (`int`, defaults to 4096) --
  The minimum number of elements of the parameter tensors for 8-bit optimization.0

Paged 8-bit Lion optimizer.

**Parameters:**

params (`torch.tensor`) : The input parameters to optimize.

lr (`float`, defaults to 1e-4) : The learning rate.

betas (`tuple(float, float)`, defaults to (0.9, 0.999)) : The beta values are the decay rates of the first and second-order moment of the optimizer.

weight_decay (`float`, defaults to 0) : The weight decay value for the optimizer.

args (`object`, defaults to `None`) : An object with additional arguments.

min_8bit_size (`int`, defaults to 4096) : The minimum number of elements of the parameter tensors for 8-bit optimization.

## PagedLion32bit[[bitsandbytes.optim.PagedLion32bit]]

#### bitsandbytes.optim.PagedLion32bit[[bitsandbytes.optim.PagedLion32bit]]

[Source](https://github.com/bitsandbytes-foundation/bitsandbytes/blob/main/bitsandbytes/optim/lion.py#L228)

__init__bitsandbytes.optim.PagedLion32bit.__init__https://github.com/bitsandbytes-foundation/bitsandbytes/blob/main/bitsandbytes/optim/lion.py#L229[{"name": "params", "val": ""}, {"name": "lr", "val": " = 0.0001"}, {"name": "betas", "val": " = (0.9, 0.99)"}, {"name": "weight_decay", "val": " = 0"}, {"name": "args", "val": " = None"}, {"name": "min_8bit_size", "val": " = 4096"}]- **params** (`torch.tensor`) --
  The input parameters to optimize.
- **lr** (`float`, defaults to 1e-4) --
  The learning rate.
- **betas** (`tuple(float, float)`, defaults to (0.9, 0.999)) --
  The beta values are the decay rates of the first and second-order moment of the optimizer.
- **weight_decay** (`float`, defaults to 0) --
  The weight decay value for the optimizer.
- **args** (`object`, defaults to `None`) --
  An object with additional arguments.
- **min_8bit_size** (`int`, defaults to 4096) --
  The minimum number of elements of the parameter tensors for 8-bit optimization.0

Paged 32-bit Lion optimizer.

**Parameters:**

params (`torch.tensor`) : The input parameters to optimize.

lr (`float`, defaults to 1e-4) : The learning rate.

betas (`tuple(float, float)`, defaults to (0.9, 0.999)) : The beta values are the decay rates of the first and second-order moment of the optimizer.

weight_decay (`float`, defaults to 0) : The weight decay value for the optimizer.

args (`object`, defaults to `None`) : An object with additional arguments.

min_8bit_size (`int`, defaults to 4096) : The minimum number of elements of the parameter tensors for 8-bit optimization.