orca/ext/wasm3/test/wasi/mandelbrot/mandel_dd.c

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2023-04-12 14:21:03 +00:00
#include <math.h>
#include <stdio.h>
#include <stdlib.h>
#include <stdbool.h>
#include <time.h>
#include "colors.h"
#include "doubledouble.h"
double get_time() {
struct timespec ts; clock_gettime(CLOCK_REALTIME, &ts);
return ts.tv_sec * 1000.0 + ts.tv_nsec / 1000000.0;
}
int main(int argc, char **argv) {
unsigned width, height;
DoubleDouble magn;
if (argc <= 1) {
width = 1024;
height = width;
magn = dd_new(4e5, 0);
} else if (argc == 3) {
width = atoi(argv[1]);
height = width;
magn = dd_new(strtod(argv[2], NULL), 0);
} else {
fprintf(stderr, "usage: %s <size> <magnification>\n", argv[0]);
return 1;
}
DoubleDouble temp1;
double eps = 1e-17;
double Q1LOG2 = 1.44269504088896340735992468100189213742664595415299;
double LOG2 = 0.69314718055994530941723212145817656807550013436026;
unsigned int x, y;
DoubleDouble centerx, centery;
centerx = dd_new(-0.7436438870371587, -3.628952515063387E-17);
centery = dd_new(0.13182590420531198, -1.2892807754956678E-17);
double bailout = 128; // with a smaller value there are lines on magn=1
double logLogBailout = log(log(bailout));
int foundperiods = 0;
long maxiter = 50000;
/*// maxiter = width * sqrt(magn);
temp1 = dd_sqrt(magn);
unsigned long maxiter = width * dd_get_ui(temp1);*/
DoubleDouble x2, y2, x0d, y1d;
// x0d = 4 / magn / width;
x0d = dd_ui_div(4, magn);
x0d = dd_div_ui(x0d, width);
// x2 = -2 / magn + centerx;
x2 = dd_si_div(-2, magn);
x2 = dd_add(x2, centerx);
// y1d = -4 / magn / width;
y1d = dd_si_div(-4, magn);
y1d = dd_div_ui(y1d, width);
// y2 = 2 / magn * height / width + centery;
y2 = dd_ui_div(2, magn);
temp1 = dd_new(height, 0);
temp1 = dd_div_ui(temp1, width);
y2 = dd_mul(y2, temp1);
y2 = dd_add(y2, centery);
DoubleDouble px, py, zx, zy, xx, yy;
double hx, hy, d;
double tbeg = get_time();
// write out image header
printf("P6 %d %d 255\n", width, height);
for (y = 0; y < height; y++) {
fprintf(stderr, "\r%.2f%%", (float)(y+1)/(height)*100);
for (x = 0; x < width; x++) {
//px = x*x0d + x2;
px = dd_mul_ui(x0d, x);
px = dd_add(px, x2);
//py = y*y1d + y2;
py = dd_mul_ui(y1d, y);
py = dd_add(py, y2);
// no Main bulb or Cardoid check to be faster
zx = dd_new(px.hi, px.lo);
zy = dd_new(py.hi, py.lo);
unsigned long i;
bool inside = true;
int check = 3;
int whenupdate = 10;
hx = 0;
hy = 0;
for (i = 1; i <= maxiter; i++) {
//xx = zx * zx;
xx = dd_sqr(zx);
//yy = zy * zy;
yy = dd_sqr(zy);
//if (xx + yy > bailout) {
if (xx.hi + yy.hi > bailout) {
inside = false;
break;
}
// iterate
//zy = 2 * zx * zy + py;
//zx = dd_mul_ui(zx, 2);
//zy = dd_mul(zx, zy);
zy = dd_add(dd_mul2(zx, zy), py);
//zx = xx - yy + px;
zx = dd_add(dd_sub(xx, yy), px);
// period checking
d = zx.hi - hx;
if (d > 0.0 ? d < eps : d > -eps) {
d = zy.hi - hy;
if (d > 0.0 ? d < eps : d > -eps) {
// Period found.
foundperiods++;
break;
}
}
if ((i & check) == 0) {
if (--whenupdate == 0) {
whenupdate = 10;
check <<= 1;
check++;
}
// period = 0;
hx = zx.hi;
hy = zy.hi;
}
}
if (inside) {
const char black[3] = {};
fwrite(black, 1, 3, stdout);
} else {
double r = sqrt(zx.hi*zx.hi + zy.hi*zy.hi);
double c = i - 1.28 + (logLogBailout - log(log(r))) * Q1LOG2;
int idx = fmod((log(c/64+1)/LOG2+0.45), 1)*(GRADIENTLENGTH-1) + 0.5;
fwrite(&colors[idx], 1, 3, stdout);
}
}
}
double tend = get_time();
fprintf(stderr, "\nElapsed time: %.2f ms\n", tend-tbeg);
//fprintf(stderr, "\n%d periods found\n", foundperiods);
return 0;
}