/* abc_la.h  User problem definitions for a specific PDE to be solved   */
/*        this includes the user choice of degree and discretization */
/*                                                                   */
/*        The problem must be well posed and the solution must be    */
/*        continuous and continuously differentiable                 */
/*                                                                   */
/* The general PDE to be solved is:                                  */
/*  a1(x,y)*uxx(x,y) + b1(x,y)*uxy(x,y) + c1(x,y)*uyy(x,y) +         */
/*  d1(x,y)*ux(x,y) + e1(x,y)*uy(x,y)  + f1(x,y)*u(x,y) = c(x,y)     */
/*                                                                   */


/* Define the region for the solution:                               */
/* xmin <= x <= xmax, ymin <= y <= ymax  using  nx by ny points      */

#define xmin  -1.0
#define xmax   1.0
#define ymin   -1.0
#define ymax    1.0
#define nx      6
#define ny      5
#define ifcheck 1

/* the user must provide all functions, even if only  return 0.0; */
/* the functions are implemented in the file  abc.c               */ 
/* A specific set of test functions is covered in abc.txt         */

double a1(double x, double y);
double b1(double x, double y);
double c1(double x, double y);
double d1(double x, double y);
double e1(double x, double y);
double f1(double x, double y);
double u(double x, double y);  /* must compute boundary, if solution, then */
                               /* set  ifcheck = 1, else ifcheck = 0       */
double c(double x, double y);  /* this becomes defined by u and a1 ... f1  */