code: def off_diagonal(x):
      # return 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()
  
file_path: lightly/tests/loss/test_barlow_twins_loss.py
imports: import pytest
  import torch
  import torch.nn
  from pytest_mock import MockerFixture
  from torch import distributed
  from lightly.loss.barlow_twins_loss import BarlowTwinsLoss
label_desc: Use image node_id 1 for calling a global function with example usage: off_diagonal(x) and returns: x