code: def gen_data(dt):
      arrays = {}
  
      if dt == np.float128:
          pg = "./fftw_longdouble"
      elif dt == np.float64:
          pg = "./fftw_double"
      elif dt == np.float32:
          pg = "./fftw_single"
      else:
          raise ValueError("unknown: %s" % dt)
      # Generate test data using FFTW for reference
      for type in [1, 2, 3, 4, 5, 6, 7, 8]:
          arrays[type] = {}
          for sz in SZ:
              a = Popen(
                  [pg, str(type), str(sz)], stdout=PIPE, stderr=STDOUT
              )
              st = [
                  i.decode("ascii").strip()
                  for i in a.stdout.readlines()
              ]
              arrays[type][sz] = np.fromstring(
                  ",".join(st), sep=",", dtype=dt
              )
  
      return arrays
  
label_desc: Use image node_id 1 for calling a global function with example usage: gen_data(dt) and returns: arrays