code: def fht(a, dln, mu, offset=0.0, bias=0.0):
      """Compute the fast Hankel transform.
  
      Computes the discrete Hankel transform of a logarithmically spaced periodic
      sequence using the FFTLog algorithm [1]_, [2]_.
  
      Parameters
      ----------
      a : cupy.ndarray (..., n)
          Real periodic input array, uniformly logarithmically spaced.  For
          multidimensional input, the transform is performed over the last axis.
      dln : float
          Uniform logarithmic spacing of the input array.
      mu : float
          Order of the Hankel transform, any positive or negative real number.
      offset : float, optional
          Offset of the uniform logarithmic spacing of the output array.
      bias : float, optional
          Exponent of power law bias, any positive or negative real number.
  
      Returns
      -------
      A : cupy.ndarray (..., n)
          The transformed output array, which is real, periodic, uniformly
          logarithmically spaced, and of the same shape as the input array.
  
      See Also
      --------
      :func:`scipy.special.fht`
      :func:`scipy.special.fhtoffset` : Return an optimal offset for `fht`.
  
      References
      ----------
      .. [1] Talman J. D., 1978, J. Comp. Phys., 29, 35
      .. [2] Hamilton A. J. S., 2000, MNRAS, 312, 257 (astro-ph/9905191)
  
      """
  
      # size of transform
      n = a.shape[-1]
  
      # bias input array
      if bias != 0:
          # a_q(r) = a(r) (r/r_c)^{-q}
          j_c = (n - 1) / 2
          j = cupy.arange(n)
          a = a * cupy.exp(-bias * (j - j_c) * dln)
  
      # compute FHT coefficients
      u = fhtcoeff(n, dln, mu, offset=offset, bias=bias)
  
      # transform
      A = _fhtq(a, u)
  
      # bias output array
      if bias != 0:
          # A(k) = A_q(k) (k/k_c)^{-q} (k_c r_c)^{-q}
          A *= cupy.exp(-bias * ((j - j_c) * dln + offset))
  
      return A
  
file_path: cupy/cupyx/scipy/fft/_fftlog.py
imports: import math
  from warnings import warn
  import cupy
  from cupyx.scipy.fft import _fft
  from cupyx.scipy.special import loggamma, poch
label_desc: Use image node_id 1 for calling a global function with example usage: fht(a, dln, mu, offset, bias) and returns: A