code: def _local_2d_gaussian_distribution(H, W, sigma=1.0):
      d = _local_2d_distance(H, W, p=2.0) ** 2
      d = torch.exp(-0.5 * sigma ** (-2.0) * d)
      return d
  
imports: import itertools
  import pytest
  import torch
  import xformers.components.attention.attention_patterns
  from xformers.components.attention.sparsity_config import BigBirdSparsityConfig, BSLongformerSparsityConfig, DenseSparsityConfig, FixedSparsityConfig, VariableSparsityConfig
label_desc: Use image node_id 6 for calling a global function with example usage: _local_2d_gaussian_distribution(H, W, sigma) and returns: d