#include <stdio.h>
#include <math.h>
#define MAXN 100000


double sor(int n, double *x, double *b, int niter, double omg)
{
   int i, iter;
   double rez, rezi; 
   for(iter = 0; iter < niter; iter++)
   {
       rez = 0;
       for(i = 1; i < n; i++)
       {
           rezi = (b[i] + x[i - 1] - 2 * x[i] + x[i + 1]) ;
           x[i] = x[i] + omg * rezi / 2;
           rezi = fabs(rezi);
           rez  = (rezi > rez) ? rezi : rez;
       }
       printf("sor: iter %d, reziduum %g \n", iter, rez);
       if (rez < 1e-12)
           break;
   }
   return rez;
}

void uloz_reseni(const char *fname, int n, double *x)
{
    FILE *fid;
    int i;

    printf("Reseni ukladam do souboru: %s \n", fname);
    fid = fopen(fname, "w");
    if (fid == NULL)
        exit(1);
    for(i = 1; i < n; i++)
        fprintf(fid, "%20.10g\n", x[i]);
    fclose(fid);
    
}

main()
{
    const maxiter = 15000;
    int n, i, k;
    double rez, h;
    double X[MAXN], XPOM[MAXN], B[MAXN];

   n = 200;  h = 1. / (n + 1);

   for(i = 1; i < n; i++)
       B[i] = h * h * sin( i * h * M_PI);
   for(i = 0; i <= n; i++)
       X[i] = 0;

   rez = sor(n, X, B, 80000, 1.7);
   printf("Finished sor \t %12.7g\n", k, rez);

   uloz_reseni("reseni.dat", n, X);
}