docs: def compute_fw_at_frac_max_1d_simple(Y, xc, X=None, f=0.5):
      """Compute the full width at fraction f of the maximum"""
  
      yy = np.asarray(Y)
  
      if yy.ndim != 1:
          raise ValueError('array must be 1-d')
  
      if yy.size == 0:
          raise ValueError('array is empty')
  
      if X is None:
          xx = np.arange(yy.shape[0])
      else:
          xx = X
  
      xpix = coor_to_pix_1d(xc - xx[0])
  
      try:
          peak = yy[xpix]
      except IndexError:
          raise ValueError('peak is out of array')
  
      fwhm_x, _codex, _msgx = compute_fwhm_1d(xx, yy - f * peak, xc, xpix)
      return peak, fwhm_x