code: def layer_inverse_covariance(layer):
      """Inverse of a layer's correlation matrix. Function exists mostly for caching."""
      return np.linalg.inv(layer_covariance(layer))
  
file_path: lucid/lucid/modelzoo/aligned_activations.py
imports: from __future__ import absolute_import, division, print_function
  from lucid.misc.io.sanitizing import sanitize
  from lucid.misc.io import load
  import numpy
  from cachetools.func import lru_cache
label_desc: Use image node_id 3 for calling a global function with example usage: layer_inverse_covariance(layer) and returns: np