path: root/tests/exec/mandelbrot.cpp

#include <iostream>

/* arithmetique de virgule fixe
   precision q = 8192 i.e. 13 bits pour la partie decimale */

int add(int x, int y) {
  return x + y;
}
int sub(int x, int y) {
  return x - y;
}
int mul(int x, int y) {
  int t = x * y;
  return (t + 8192 / 2) / 8192;
}
int div(int x, int y) {
  int t = x * 8192;
  return (t + y / 2) / y;
}
int of_int(int x) {
  return x * 8192;
}

int iter(int n, int a, int b, int xn, int yn) {
  if (n == 100) return true;
  int xn2 = mul(xn, xn);
  int yn2 = mul(yn, yn);
  if (add(xn2, yn2) > of_int(4)) return false;
  return iter(n+1, a, b, add(sub(xn2, yn2), a),
              add(mul(of_int(2), mul(xn, yn)), b));
}

int inside(int x, int y) {
  return iter(0, x, y, of_int(0), of_int(0));
}

int main() {
  int steps = 30;
  int xmin = of_int(-2);
  int xmax = of_int(1);
  int deltax = div(sub(xmax, xmin), of_int(2 * steps));
  int ymin = of_int(-1);
  int ymax = of_int(1);
  int deltay = div(sub(ymax, ymin), of_int(steps));
  int i;
  for (i = 0; i < steps; i++) {
    int y = add(ymin, mul(of_int(i), deltay));
    int j;
    for (j = 0; j < 2 * steps; j++) {
      int x = add(xmin, mul(of_int(j), deltax));
      if (inside(x, y))
        std::cout << "0";
      else
        std::cout << "1";
    }
    std::cout << "\n";
  }
}