code: def correlation(y_true, y_pred, axis=None):
      """Pearson's product moment correlation coefficient"""
      return covariance(y_true, y_pred, axis=axis) / T.sqrt(
          variance(y_true, axis) * variance(y_pred, axis)
      )
  
file_path: tensorly/tensorly/metrics/regression.py
imports: from ..None import backend
label_desc: Use image node_id 8 for calling a global function with example usage: correlation(y_true, y_pred, axis) and returns: unknown