typedef struct
  int    x;       //x coordinate
  int    y;       //y coordinate
  int    z;       //z coordinate
  float  mb;      //mass of baryon
  float  mp;      //mass of phantom dark matter
  float  pn;       //potential of Newton
  float  pp;       //potential of phantom dark matter
  float  accp;       //acceleration of phantom dark matter
  float  vc;         //circular velocity
Grid;
Algorithm 1