# ifndef H_POISSON_H
# define H_POISSON_H

# include "ppc_mesh.h"
# include "ppc_poisson_spec.h"
# include "ppc_twb_quad.h"

struct errors
{
  double Linfty;
  double L2norm;
  double energy;
};

void compute_element_stiffness ( struct elem *ep, struct TWB_qdat *qdat,
  int d, double (*f)(double x, double y), double k[3][4] );
void enforce_zero_dirichlet_bc ( struct elem *ep, double k[3][4] );
void error_and_exit ( int status, const char *file, int line );
struct errors element_errors ( struct problem_spec *spec, 
  struct TWB_qdat *qdat, struct elem *ep, int d );
struct errors eval_errors ( struct problem_spec *spec, struct mesh *mesh,
  int d );
void poisson_solve ( struct problem_spec *spec, struct mesh *mesh, int d );

# endif