class_docstr: The Resels class.
      
class_docstr_tok: ["The","Resels","class","."]
docstr: Integrate resels within `mask` (or use self.mask)
  
  Parameters
  ----------
  mask : ``Image``
          Optional mask over which to integrate (add) resels.
  
  Returns
  -------
  total_resels :
      the resels contained in the mask
  FWHM : float
      an estimate of FWHM based on the average resel per voxel
  nvoxel: int
      the number of voxels in the mask
docstr_tok: ["Integrate","resels","within","`","mask","`","(","or","use","self.mask",")","Parameters","--","--","--","--","--","mask",":","``","Image","``","Optional","mask","over","which","to","integrate","(","add",")","resels",".","Returns","--","--","--","-","total_resels",":","the","resels","contained","in","the","mask","FWHM",":","float","an","estimate","of","FWHM","based","on","the","average","resel","per","voxel","nvoxel",":","int","the","number","of","voxels","in","the","mask"]
code: def integrate(self, mask=None):
      """Integrate resels within `mask` (or use self.mask)
  
      Parameters
      ----------
      mask : ``Image``
              Optional mask over which to integrate (add) resels.
  
      Returns
      -------
      total_resels :
          the resels contained in the mask
      FWHM : float
          an estimate of FWHM based on the average resel per voxel
      nvoxel: int
          the number of voxels in the mask
      """
      _resels = self.resels[:]
      if mask is not None:
          _mask = mask
      else:
          _mask = self.mask
      if _mask is not None:
          _mask = _mask[:].astype(np.int32)
          nvoxel = _mask.sum()
      else:
          _mask = 1.0
          nvoxel = _resels.size
      _resels = (_resels * _mask).sum()
      _fwhm = self.resel2fwhm(_resels / nvoxel)
      return _resels, _fwhm, nvoxel
  
file_path: nipy/nipy/algorithms/fwhm.py
imports: import numpy
  from numpy.linalg import det
  from nipy.core.api import Image
  from .utils.matrices import pos_recipr
label_desc: Use image node_id 2 for calling the Resels obj's underlying member method code with example usage: obj.integrate(mask) and returns: _resels,  _fwhm,  nvoxel