src/test/tag1.c

#include "utils.h"
#include "fractions.h"
#include "tag.h"

#define LEVEL 10

double geom (double x, double y) {
  double C1 = sq(x - 0.2) + sq(y) - sq(0.1);
  double C2 = sq(x - 0.8) + sq(y) - sq(0.01);

  double C1C2 = min(C1, C2);
  return - C1C2;
}

int main()
{
  init_grid (1<<9);

  scalar f[];
  f.refine = f.prolongation = fraction_refine;
  
  double iteration = 0;
  do {
    iteration++;
    fraction (f, geom(x,y));
  } while (adapt_wavelet({f}, (double []){0.005}, maxlevel = LEVEL, 5).nf != 0
	   && iteration <= 10);

  scalar m[];
  foreach()
    m[] = f[] > 1.e-3;
  int n = tag(m);

  output_ppm (m, file = "tag.ppm", min = 0, max = n);
  
  if (n != 2) {
    dump ("error");
    exit (1); // error
  }
}