code: def test_tau():
      assert (
          normalised_kendall_tau_distance(
              np.arange(400), np.arange(400)
          )
          == 0
      )
      assert (
          normalised_kendall_tau_distance(
              np.arange(2000), np.arange(2000)
          )
          == 0
      )
      a = np.array([1, 2, 3, 4, 5])
      b = np.array([3, 4, 1, 2, 5])
      assert normalised_kendall_tau_distance(a, b) == 0.4
      i, j = np.meshgrid(np.arange(len(a)), np.arange(len(b)))
      assert normalised_kendall_tau_distance(a, b, i, j) == 0.4
      assert normalised_kendall_tau_distance(a, a, i, j) == 0
  
      try:
          normalised_kendall_tau_distance(np.arange(5), np.arange(10))
          raise Exception("expect error")
      except AssertionError:
          pass
  
file_path: ultranest/tests/test_utils.py
imports: import numpy
  import tempfile
  import os
  from ultranest.utils import vectorize, is_affine_transform, normalised_kendall_tau_distance, make_run_dir
  from ultranest.utils import distributed_work_chunk_size
  from numpy.testing import assert_allclose
  import pytest
label_desc: Use image node_id 3 for calling a global function with example usage: test_tau() without return types