CosineAnnealingScheduler

class composer.optim.CosineAnnealingScheduler(t_max='1dur', alpha_f=0.0)

Decays the learning rate according to the decreasing part of a cosine curve.

See also

This scheduler is based on CosineAnnealingLR from PyTorch.

Specifically, the learning rate multiplier $\alpha$ can be expressed as:

$$\alpha(t) = \alpha_f + (1 - \alpha_f) \times \frac{1}{2} (1 + \cos(\pi \times \tau))$$

Given $\tau$, the fraction of time elapsed (clipped to the interval $[0, 1]$), as:

$$\tau = t / t_{max}$$

Where $t_{max}$ represents the duration of this scheduler, and $\alpha_f$ represents the learning rate multiplier to decay to.

Parameters

• t_max (str | Time) – The duration of this scheduler. Default = "1dur".

• alpha_f (float) – Learning rate multiplier to decay to. Default = 0.0.