Source code for mmpretrain.models.losses.cross_correlation_loss
# Copyright (c) OpenMMLab. All rights reserved.
import torch
from mmengine.model import BaseModule
from mmpretrain.registry import MODELS
[docs]@MODELS.register_module()
class CrossCorrelationLoss(BaseModule):
"""Cross correlation loss function.
Compute the on-diagnal and off-diagnal loss.
Args:
lambd (float): The weight for the off-diag loss.
"""
def __init__(self, lambd: float = 0.0051) -> None:
super().__init__()
self.lambd = lambd
[docs] def forward(self, cross_correlation_matrix: torch.Tensor) -> torch.Tensor:
"""Forward function of cross correlation loss.
Args:
cross_correlation_matrix (torch.Tensor): The cross correlation
matrix.
Returns:
torch.Tensor: cross correlation loss.
"""
# loss
on_diag = torch.diagonal(cross_correlation_matrix).add_(-1).pow_(
2).sum()
off_diag = self.off_diagonal(cross_correlation_matrix).pow_(2).sum()
loss = on_diag + self.lambd * off_diag
return loss
[docs] def off_diagonal(self, x: torch.Tensor) -> torch.Tensor:
"""Rreturn a flattened view of the off-diagonal elements of a square
matrix."""
n, m = x.shape
assert n == m
return x.flatten()[:-1].view(n - 1, n + 1)[:, 1:].flatten()