code: def gamma_params(peak_location, peak_fwhm):
      """Parameters for gamma density given peak and width
  
      TODO: where does the coef come from again.... check fmristat code
  
      From a peak location and peak FWHM, determine the parameters (shape,
      scale) of a Gamma density:
  
      f(x) = coef * x**(shape-1) * exp(-x/scale)
  
      The coefficient returned ensures that the f has integral 1 over
      [0,np.inf]
  
      Parameters
      ----------
      peak_location : float
         Location of the peak of the Gamma density
      peak_fwhm : float
         FWHM at the peak
  
      Returns
      -------
      shape : float
         Shape parameter in the Gamma density
      scale : float
         Scale parameter in the Gamma density
      coef : float
         Coefficient needed to ensure the density has integral 1.
      """
      shape_m1 = (
          np.power(peak_location / peak_fwhm, 2) * 8 * np.log(2.0)
      )
      scale = np.power(peak_fwhm, 2) / peak_location / 8 / np.log(2.0)
      coef = peak_location ** (-shape_m1) * np.exp(
          peak_location / scale
      )
      return shape_m1 + 1, scale, coef
  
file_path: nipy/nipy/modalities/fmri/hrf.py
imports: from functools import partial
  import numpy
  import scipy.stats
  import sympy
  from sympy.utilities.lambdify import implemented_function
  from .utils import T, lambdify_t
label_desc: Use image node_id 1 for calling a global function with example usage: gamma_params(peak_location, peak_fwhm) and returns: unknown,  scale,  coef