Bitsandbytes documentation

SGD

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SGD

Stochastic gradient descent (SGD) is a basic gradient descent optimizer to minimize loss given a set of model parameters and updates the parameters in the opposite direction of the gradient. The update is performed on a randomly sampled mini-batch of data from the dataset.

bitsandbytes also supports momentum and Nesterov momentum to accelerate SGD by adding a weighted average of past gradients to the current gradient.

SGD

class bitsandbytes.optim.SGD

< >

( params lr momentum = 0 dampening = 0 weight_decay = 0 nesterov = False optim_bits = 32 args = None min_8bit_size = 4096 percentile_clipping = 100 block_wise = True )

__init__

< >

( params lr momentum = 0 dampening = 0 weight_decay = 0 nesterov = False optim_bits = 32 args = None min_8bit_size = 4096 percentile_clipping = 100 block_wise = True )

Parameters

  • params (torch.tensor) — The input parameters to optimize.
  • lr (float) — The learning rate.
  • momentum (float, defaults to 0) — The momentum value speeds up the optimizer by taking bigger steps.
  • dampening (float, defaults to 0) — The dampening value reduces the momentum of the optimizer.
  • weight_decay (float, defaults to 0.0) — The weight decay value for the optimizer.
  • nesterov (bool, defaults to False) — Whether to use Nesterov momentum.
  • 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.
  • percentile_clipping (int, defaults to 100) — Adapts clipping threshold automatically by tracking the last 100 gradient norms and clipping the gradient at a certain percentile to improve stability.
  • block_wise (bool, defaults to True) — Whether to independently quantize each block of tensors to reduce outlier effects and improve stability.

Base SGD optimizer.

SGD8bit

class bitsandbytes.optim.SGD8bit

< >

( params lr momentum = 0 dampening = 0 weight_decay = 0 nesterov = False args = None min_8bit_size = 4096 percentile_clipping = 100 block_wise = True )

__init__

< >

( params lr momentum = 0 dampening = 0 weight_decay = 0 nesterov = False args = None min_8bit_size = 4096 percentile_clipping = 100 block_wise = True )

Parameters

  • params (torch.tensor) — The input parameters to optimize.
  • lr (float) — The learning rate.
  • momentum (float, defaults to 0) — The momentum value speeds up the optimizer by taking bigger steps.
  • dampening (float, defaults to 0) — The dampening value reduces the momentum of the optimizer.
  • weight_decay (float, defaults to 0.0) — The weight decay value for the optimizer.
  • nesterov (bool, defaults to False) — Whether to use Nesterov momentum.
  • 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.
  • percentile_clipping (int, defaults to 100) — Adapts clipping threshold automatically by tracking the last 100 gradient norms and clipping the gradient at a certain percentile to improve stability.
  • block_wise (bool, defaults to True) — Whether to independently quantize each block of tensors to reduce outlier effects and improve stability.

8-bit SGD optimizer.

SGD32bit

class bitsandbytes.optim.SGD32bit

< >

( params lr momentum = 0 dampening = 0 weight_decay = 0 nesterov = False args = None min_8bit_size = 4096 percentile_clipping = 100 block_wise = True )

__init__

< >

( params lr momentum = 0 dampening = 0 weight_decay = 0 nesterov = False args = None min_8bit_size = 4096 percentile_clipping = 100 block_wise = True )

Parameters

  • params (torch.tensor) — The input parameters to optimize.
  • lr (float) — The learning rate.
  • momentum (float, defaults to 0) — The momentum value speeds up the optimizer by taking bigger steps.
  • dampening (float, defaults to 0) — The dampening value reduces the momentum of the optimizer.
  • weight_decay (float, defaults to 0.0) — The weight decay value for the optimizer.
  • nesterov (bool, defaults to False) — Whether to use Nesterov momentum.
  • 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.
  • percentile_clipping (int, defaults to 100) — Adapts clipping threshold automatically by tracking the last 100 gradient norms and clipping the gradient at a certain percentile to improve stability.
  • block_wise (bool, defaults to True) — Whether to independently quantize each block of tensors to reduce outlier effects and improve stability.

32-bit SGD optimizer.

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