text: #ifndef KRYLOV_H
  #define KRYLOV_H 
  
  typedef struct {
  
    p4est_t* p4est;
    d4est_elliptic_data_t* vecs;
    void* fcns;
    p4est_ghost_t** ghost;
    void** ghost_data;
    d4est_operators_t* d4est_ops;
    d4est_geometry_t* d4est_geom;
    
  } krylov_ctx_t;
  
  #endif
  