mmcls.models.FocalLoss

class mmcls.models.FocalLoss(gamma=2.0, alpha=0.25, reduction='mean', loss_weight=1.0)

Focal loss.

Parameters

• gamma (float) – Focusing parameter in focal loss. Defaults to 2.0.

• alpha (float) – The parameter in balanced form of focal loss. Defaults to 0.25.

• reduction (str) – The method used to reduce the loss into a scalar. Options are “none” and “mean”. Defaults to ‘mean’.

• loss_weight (float) – Weight of loss. Defaults to 1.0.