-
Notifications
You must be signed in to change notification settings - Fork 0
/
binary-decomposition.c
60 lines (49 loc) · 1.28 KB
/
binary-decomposition.c
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
#include <complex.h>
#include <math.h>
#include <stdio.h>
#include <stdlib.h>
#include <omp.h> //OpenM
/*
fork of
mandelbrot-book how to write a book about the Mandelbrot set by Claude Heiland-Alle
https://code.mathr.co.uk/mandelbrot-book/blob/HEAD:/book/
gcc binary-decomposition.c -lm -Wall -fopenmp
./a.out >bd.pgm
*/
double cnorm(double _Complex z)
{
return creal(z) * creal(z) + cimag(z) * cimag(z);
}
int main()
{
//int aa = 4;
int w = 2000 ; // width in piels
int h = 2000 ; // height in pixels
int kMax = 1024; // iteration max
double r = 2; // radius: https://en.wikibooks.org/wiki/Fractals/Computer_graphic_techniques/2D/plane#radius
double r2 = 25 * 25; // escape_radius^2
unsigned char *img = malloc(w * h);
#pragma omp parallel for
for (int j = 0; j < h; ++j)
{
double y = (h/2 - (j + 0.5)) / (h/2) * r;
for (int i = 0; i < w; ++i)
{
double x = (i + 0.5 - w/2) / (h/2) * r;
double _Complex c = x + I * y;
double _Complex z = 0;
int k;
for (k = 0; k < kMax; ++k)
{
z = z * z + c;
if (cnorm(z) > r2)
break;
}
img[j * w + i] = (k < kMax && cimag(z) < 0) ? 0 : 255;
}
}
printf("P5\n%d %d\n255\n", w, h);
fwrite(img, w * h, 1, stdout);
free(img);
return 0;
}