class_docstr: Applies a displacement field to a point set given in vtk format.
  Any discrete deformation field, given in physical coordinates and
  which volume covers the extent of the vtk point set, is a valid
  ``warp`` file. FSL interfaces are compatible, for instance any
  field computed with :class:`nipype.interfaces.fsl.utils.ConvertWarp`.
  
  Example::
  
      from nipype.algorithms.mesh import WarpPoints
      wp = WarpPoints()
      wp.inputs.points = 'surf1.vtk'
      wp.inputs.warp = 'warpfield.nii'
      res = wp.run()
code: def _gen_fname(self, in_file, suffix="generated", ext=None):
      fname, fext = op.splitext(op.basename(in_file))
  
      if fext == ".gz":
          fname, fext2 = op.splitext(fname)
          fext = fext2 + fext
  
      if ext is None:
          ext = fext
  
      if ext[0] == ".":
          ext = ext[1:]
      return op.abspath(f"{fname}_{suffix}.{ext}")
  
imports: import os.path
  import numpy
  from numpy import linalg
  from ..None import logging
  from ..interfaces.base import BaseInterface, traits, TraitedSpec, File, BaseInterfaceInputSpec
  from ..interfaces.vtkbase import tvtk
  from ..interfaces import vtkbase
label_desc: Use image node_id 1 for calling the WarpPoints obj's underlying member method code with example usage: obj._gen_fname(in_file, suffix, ext) and returns: op