code: def test_fht_exact(n):
      rng = np.random.RandomState(3491349965)
  
      # for a(r) a power law r^\gamma, the fast Hankel transform produces the
      # exact continuous Hankel transform if biased with q = \gamma
  
      mu = rng.uniform(0, 3)
  
      # convergence of HT: -1-mu < gamma < 1/2
      gamma = rng.uniform(-1 - mu, 1 / 2)
  
      r = np.logspace(-2, 2, n)
      a = r**gamma
  
      dln = np.log(r[1] / r[0])
  
      offset = fhtoffset(dln, mu, initial=0.0, bias=gamma)
  
      A = fht(a, dln, mu, offset=offset, bias=gamma)
  
      k = np.exp(offset) / r[::-1]
  
      # analytical result
      At = (2 / k) ** gamma * poch((mu + 1 - gamma) / 2, gamma)
  
      assert_allclose(A, At)
  
file_path: catboost/contrib/python/scipy/py3/scipy/fft/tests/test_fftlog.py
imports: import numpy
  from numpy.testing import assert_allclose
  import pytest
  from scipy.fft._fftlog import fht, ifht, fhtoffset
  from scipy.special import poch
label_desc: Use image node_id 4 for calling a global function with example usage: test_fht_exact(n) without return types