text: #include <THC/THC.h>
  
  void gpu_computeCoords2Volume(	double *coords,
                                  int *num_atoms_of_type,
  							    int *offsets, 
  								float *volume,
  								int spatial_dim,
                                  int num_atom_types,
  								float res);
  
  void gpu_computeVolume2Coords(	double *coords,
  								double* grad,
                                  int *num_atoms_of_type,
  							    int *offsets, 
  								float *volume,
  								int spatial_dim,
                                  int num_atom_types,
  								float res);
  
  void gpu_selectFromTensor(	float *features, int num_features, 
  							float* volume, int spatial_dim, 
  							float *coords, int num_atoms, int max_num_atoms, 
  							float res);