code: def get_synthetic_warped_circle(nslices):
      # get a subsampled circle
      fname_cicle = get_fnames("reg_o")
      circle = np.load(fname_cicle)[::4, ::4].astype(floating)
  
      # create a synthetic invertible map and warp the circle
      d, dinv = vfu.create_harmonic_fields_2d(64, 64, 0.1, 4)
      d = np.asarray(d, dtype=floating)
      dinv = np.asarray(dinv, dtype=floating)
      mapping = DiffeomorphicMap(2, (64, 64))
      mapping.forward, mapping.backward = d, dinv
      wcircle = mapping.transform(circle)
  
      if nslices == 1:
          return circle, wcircle
  
      # normalize and form the 3d by piling slices
      circle = (circle - circle.min()) / (circle.max() - circle.min())
      circle_3d = np.ndarray(circle.shape + (nslices,), dtype=floating)
      circle_3d[...] = circle[..., None]
      circle_3d[..., 0] = 0
      circle_3d[..., -1] = 0
  
      # do the same with the warped circle
      wcircle = (wcircle - wcircle.min()) / (
          wcircle.max() - wcircle.min()
      )
      wcircle_3d = np.ndarray(
          wcircle.shape + (nslices,), dtype=floating
      )
      wcircle_3d[...] = wcircle[..., None]
      wcircle_3d[..., 0] = 0
      wcircle_3d[..., -1] = 0
  
      return circle_3d, wcircle_3d
  
imports: import numpy
  import nibabel.eulerangles
  from numpy.testing import assert_equal, assert_array_equal, assert_array_almost_equal, assert_raises
  from dipy.core.interpolation import interpolate_scalar_2d, interpolate_scalar_3d
  from dipy.data import get_fnames
  from dipy.align import floating
  from dipy.align import imwarp
  from dipy.align import metrics
  from dipy.align import vector_fields
  from dipy.align import VerbosityLevels
  from dipy.align.imwarp import DiffeomorphicMap
  from dipy.tracking.streamline import deform_streamlines
  from dipy.testing.decorators import set_random_number_generator
label_desc: Use image node_id 11 for calling a global function with example usage: get_synthetic_warped_circle(nslices) and returns: circle_3d,  wcircle_3d, circle,  wcircle