code: def test_mapmri_laplacian_anisotropic(radial_order=6):
      gtab = get_gtab_taiwan_dsi()
      l1, l2, l3 = [0.0015, 0.0003, 0.0003]
      S = single_tensor(gtab, evals=np.r_[l1, l2, l3])
  
      mapm = MapmriModel(
          gtab,
          radial_order=radial_order,
          laplacian_regularization=False,
      )
      mapfit = mapm.fit(S)
      tau = 1 / (4 * np.pi**2)
  
      # ground truth norm of laplacian of tensor
      norm_of_laplacian_gt = (
          (
              3 * (l1**2 + l2**2 + l3**2)
              + 2 * l2 * l3
              + 2 * l1 * (l2 + l3)
          )
          * (np.pi ** (5 / 2.0) * tau)
          / (np.sqrt(2 * l1 * l2 * l3 * tau))
      )
  
      # check if estimated laplacian corresponds with ground truth
      laplacian_matrix = mapmri.mapmri_laplacian_reg_matrix(
          mapm.ind_mat, mapfit.mu, mapm.S_mat, mapm.T_mat, mapm.U_mat
      )
  
      coef = mapfit._mapmri_coef
      norm_of_laplacian = np.dot(np.dot(coef, laplacian_matrix), coef)
  
      assert_almost_equal(norm_of_laplacian, norm_of_laplacian_gt)
  
imports: import platform
  import time
  from math import factorial
  from scipy.special import gamma
  import scipy.integrate
  import warnings
  import numpy
  from numpy.testing import assert_almost_equal, assert_array_almost_equal, assert_equal, assert_, assert_raises
  import pytest
  from dipy.core.sphere_stats import angular_similarity
  from dipy.core.subdivide_octahedron import create_unit_sphere
  from dipy.data import get_gtab_taiwan_dsi, default_sphere
  from dipy.direction.peaks import peak_directions
  from dipy.reconst.mapmri import MapmriModel, mapmri_index_matrix
  from dipy.reconst import dti, mapmri
  from dipy.reconst.odf import gfa
  from dipy.reconst.tests.test_dsi import sticks_and_ball_dummies
  from dipy.reconst.shm import sh_to_sf, descoteaux07_legacy_msg
  from dipy.sims.voxel import multi_tensor, multi_tensor_pdf, add_noise, single_tensor, cylinders_and_ball_soderman
  from dipy.testing.decorators import set_random_number_generator
label_desc: Use image node_id 15 for calling a global function with example usage: test_mapmri_laplacian_anisotropic(radial_order) without return types