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varmfskiivarmfskii
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In C with improved thread handling.
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4 files changed

+424
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‎modern/build_c.sh‎

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#!/bin/bash
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for i in {1,2,4,6,8,12}
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do
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echo "Speccy standard, 32x22, 15 max iteration, $i thread"
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gcc -o man_speccy_$i -Ofast -DWIDTH=32 -DHEIGHT=22 -DMAX_ITER=15 -DNUM_THREADS=$i mandelbrot.c -lpthread
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done
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for i in {1,2,4,6,8,12}
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do
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echo "EGA/NTSC standard, 320x200, 16 max iteration, $i thread"
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gcc -o man_ega_$i -Ofast -DWIDTH=320 -DHEIGHT=200 -DMAX_ITER=16 -DNUM_THREADS=$i mandelbrot.c -lpthread
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done
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for i in {1,2,4,6,8,12,16,24,32,48,64,96,128}
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do
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echo "4K UHD, 3840x2160, 2000 max iteration, $i thread"
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gcc -o man_4k_2000_$i -Ofast -DWIDTH=3840 -DHEIGHT=2160 -DMAX_ITER=2000 -DNUM_THREADS=$i mandelbrot.c -lpthread
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done

‎modern/mandelbrot.c‎

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#include <stdio.h>
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#include <stdlib.h>
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#include <pthread.h>
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#ifndef WIDTH
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#define WIDTH 3840
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#endif
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#ifndef HEIGHT
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#define HEIGHT 2160
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#endif
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#ifndef MAX_ITER
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#define MAX_ITER 2000
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#endif
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#ifndef NUM_THREADS
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#define NUM_THREADS 12
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#endif
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#if NUM_THREADS > HEIGHT
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#error "Can't have more threads than pixel rows!"
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#endif
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void set_pixel(unsigned char *img, int x, int y, unsigned char *color);
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unsigned char *create_image(int w, int h);
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void write_ppm(char *name, int w, int h, unsigned char *img);
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unsigned char **palette;
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unsigned char cga_palette[16][3] = { // CGA 16-color palette, as RGB
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{0x00,0x00,0x00},
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{0x00,0x00,0xAA},
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{0x00,0xAA,0x00},
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{0x00,0xAA,0xAA},
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{0xAA,0x00,0x00},
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{0xAA,0x00,0xAA},
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{0xAA,0x55,0x00},
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{0xAA,0xAA,0xAA},
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{0x55,0x55,0x55},
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{0x55,0x55,0xFF},
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{0x55,0xFF,0x55},
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{0x55,0xFF,0xFF},
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{0xFF,0x55,0x55},
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{0xFF,0x55,0xFF},
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{0xFF,0xFF,0x55},
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{0xFF,0xFF,0xFF}
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};
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int next_row=0;
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pthread_mutex_t lock;
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unsigned char *img;
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void dorow(int py) {
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int px,i;
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double xz,yz,x,y,xt;
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for (px=0; px<WIDTH; px++) {
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xz = (double)px*3.5/WIDTH-2.5;
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yz = (double)py*2.0/HEIGHT-1.0;
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x = 0.0;
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y = 0.0;
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for (i=0; i<MAX_ITER; i++) {
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if (x*x+y*y > 4) {
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break;
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}
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xt = x*x - y*y + xz;
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y = 2*x*y + yz;
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x = xt;
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}
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if (i >= MAX_ITER) {
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i = 0;
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}
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set_pixel(img, px, py, palette[i]);
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}
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}
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void *rowthread(void *v) {
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int row;
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for(;;) {
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pthread_mutex_lock(&lock);
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row=next_row++;
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pthread_mutex_unlock(&lock);
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if(row>=HEIGHT) break;
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dorow(row);
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}
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}
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int main() {
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double start, end;
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struct timespec tspec;
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int py,i;
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pthread_t rowthreads[NUM_THREADS-1];
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img = create_image(WIDTH, HEIGHT);
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palette=malloc(MAX_ITER*sizeof(unsigned char *));
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for (int j=0; j<MAX_ITER; j++) palette[j]=malloc(3*sizeof(unsigned char));
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clock_gettime(CLOCK_REALTIME, &tspec);
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start = tspec.tv_sec+1e-9*tspec.tv_nsec;
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for (i=0; i<MAX_ITER; i++) {
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if (i<16) {
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palette[i][0] = cga_palette[i][0];
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palette[i][1] = cga_palette[i][1];
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palette[i][2] = cga_palette[i][2];
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} else if (i % 16 == 0) {
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palette[i][0] = i & 0x10 ? 255 : 0;
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palette[i][1] = i & 0x20 ? 255 : 0;
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palette[i][2] = i & 0x40 ? 255 : 0;
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if ((i & 0x70) == 0) {
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palette[i][0] = 255;
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palette[i][1] = 128;
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}
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} else {
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palette[i][0] = palette[i-1][0] > 16 ? palette[i-1][0] - 16 : 0;
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palette[i][1] = palette[i-1][1] > 16 ? palette[i-1][1] - 16 : 0;
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palette[i][2] = palette[i-1][2] > 16 ? palette[i-1][2] - 16 : 0;
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}
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}
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for (i=0; i<NUM_THREADS-1; i++)
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pthread_create(rowthreads+i, NULL, rowthread, NULL);
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rowthread(NULL);
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for(i=0; i<NUM_THREADS-1; i++) pthread_join(rowthreads[i], NULL);
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write_ppm("mandelbrot.ppm", WIDTH, HEIGHT, img);
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clock_gettime(CLOCK_REALTIME, &tspec);
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end = tspec.tv_sec+1e-9*tspec.tv_nsec;
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printf("Elapsed Time: %f s\n", end-start);
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return 0;
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}
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unsigned char *create_image(int w, int h) {
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unsigned char *rv;
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return rv = malloc(w*h*3);
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}
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void set_pixel(unsigned char *img, int x, int y, unsigned char *color) {
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img[3*(x+y*WIDTH)+0] = color[0]; // Red
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img[3*(x+y*WIDTH)+1] = color[1]; // Green
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img[3*(x+y*WIDTH)+2] = color[2]; // Blue
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}
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void write_ppm(char *name, int w, int h, unsigned char *img) {
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FILE *out;
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if (!(out=fopen(name, "w"))) {
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fprintf(stderr, "Unable to open %s for writing\n", name);
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return;
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}
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fprintf(out, "P6\n%d %d\n255\n", WIDTH, HEIGHT);
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fwrite(img, 3, w*h, out);
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fclose(out);
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}
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‎modern/mandelbrot_2.c‎

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#include <stdio.h>
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#include <stdlib.h>
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#include <pthread.h>
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#include <getopt.h>
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#include <errno.h>
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#ifndef WIDTH
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#define WIDTH 3840
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#endif
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#ifndef HEIGHT
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#define HEIGHT 2160
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#endif
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#ifndef MAX_ITER
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#define MAX_ITER 2000
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#endif
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#ifndef NUM_THREADS
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#define NUM_THREADS 12
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#endif
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#if NUM_THREADS > HEIGHT
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#error "Can't have more threads than pixel rows!"
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#endif
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void set_pixel(unsigned char *img, int x, int y, unsigned char *color);
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unsigned char *create_image(int w, int h);
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void write_ppm(char *name, int w, int h, unsigned char *img);
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unsigned char **palette;
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unsigned char cga_palette[16][3] = { // CGA 16-color palette, as RGB
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{0x00,0x00,0x00},
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{0x00,0x00,0xAA},
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{0x00,0xAA,0x00},
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{0x00,0xAA,0xAA},
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{0xAA,0x00,0x00},
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{0xAA,0x00,0xAA},
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{0xAA,0x55,0x00},
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{0xAA,0xAA,0xAA},
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{0x55,0x55,0x55},
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{0x55,0x55,0xFF},
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{0x55,0xFF,0x55},
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{0x55,0xFF,0xFF},
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{0xFF,0x55,0x55},
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{0xFF,0x55,0xFF},
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{0xFF,0xFF,0x55},
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{0xFF,0xFF,0xFF}
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};
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int next_row=0;
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pthread_mutex_t lock;
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unsigned char *img;
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int width=WIDTH;
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int height=HEIGHT;
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int max_iter=MAX_ITER;
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int num_threads=NUM_THREADS;
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void dorow(int py) {
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int px,i;
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double xz,yz,x,y,xt;
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for (px=0; px<width; px++) {
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xz = (double)px*3.5/width-2.5;
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yz = (double)py*2.0/height-1.0;
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x = 0.0;
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y = 0.0;
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for (i=0; i<max_iter; i++) {
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if (x*x+y*y > 4) {
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break;
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}
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xt = x*x - y*y + xz;
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y = 2*x*y + yz;
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x = xt;
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}
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if (i >= max_iter) {
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i = 0;
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}
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set_pixel(img, px, py, palette[i]);
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}
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}
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void *rowthread(void *v) {
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int row;
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for(;;) {
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pthread_mutex_lock(&lock);
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row=next_row++;
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pthread_mutex_unlock(&lock);
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if(row>=height) break;
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dorow(row);
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}
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}
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int main(int argc, char *argv[]) {
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double start, end;
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struct timespec tspec;
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int py,i, opt;
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pthread_t *rowthreads;
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char opts[]="h:i:t:w:";
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struct option long_opts[] = {
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{ "height", 1, NULL, 'h'},
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{ "width", 1, NULL, 'w'},
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{ "iterations", 1, NULL, 'i'},
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{ "max_iter", 1, NULL, 'i'},
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{ "threads", 1, NULL, 't'},
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{ "num_threads", 1, NULL, 't'},
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{ NULL, 0, NULL, '\0'}
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};
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while((opt=getopt_long(argc, argv, opts, long_opts, NULL))!=-1) {
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switch(opt) {
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case 'h':
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errno = 0;
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height = strtol(optarg, NULL, 10);
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if (errno || height<=0) {
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fprintf(stderr, "Invalid height: %s\n", optarg);
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return -1;
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}
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break;
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case 'i':
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errno = 0;
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max_iter = strtol(optarg, NULL, 10);
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if (errno || max_iter<=0) {
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fprintf(stderr, "Invalid number of iterations: %s\n", optarg);
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return -1;
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}
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break;
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case 'w':
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errno = 0;
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width = strtol(optarg, NULL, 10);
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if (errno || width<=0) {
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fprintf(stderr, "Invalid width: %s\n", optarg);
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return -1;
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}
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break;
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case 't':
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errno = 0;
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num_threads = strtol(optarg, NULL, 10);
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if (errno || num_threads<=0) {
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fprintf(stderr, "Invalid number of threads: %s\n", optarg);
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return -1;
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}
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break;
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}
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}
148+
if (num_threads>height) {
149+
fprintf(stderr, "Number of threads (%d) cannot be greater than height (%d)\n", num_threads, height);
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return -1;
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}
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rowthreads = malloc(sizeof(pthread_t)*num_threads);
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img = create_image(width, height);
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palette=malloc(max_iter*sizeof(unsigned char *));
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for (int j=0; j<max_iter; j++) palette[j]=malloc(3*sizeof(unsigned char));
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clock_gettime(CLOCK_REALTIME, &tspec);
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start = tspec.tv_sec+1e-9*tspec.tv_nsec;
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for (i=0; i<max_iter; i++) {
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if (i<16) {
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palette[i][0] = cga_palette[i][0];
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palette[i][1] = cga_palette[i][1];
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palette[i][2] = cga_palette[i][2];
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} else if (i % 16 == 0) {
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palette[i][0] = i & 0x10 ? 255 : 0;
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palette[i][1] = i & 0x20 ? 255 : 0;
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palette[i][2] = i & 0x40 ? 255 : 0;
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if ((i & 0x70) == 0) {
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palette[i][0] = 255;
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palette[i][1] = 128;
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}
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} else {
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palette[i][0] = palette[i-1][0] > 16 ? palette[i-1][0] - 16 : 0;
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palette[i][1] = palette[i-1][1] > 16 ? palette[i-1][1] - 16 : 0;
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palette[i][2] = palette[i-1][2] > 16 ? palette[i-1][2] - 16 : 0;
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}
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}
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for (i=0; i<num_threads-1; i++)
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pthread_create(rowthreads+i, NULL, rowthread, NULL);
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rowthread(NULL);
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for(i=0; i<num_threads-1; i++) pthread_join(rowthreads[i], NULL);
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write_ppm("mandelbrot.ppm", width, height, img);
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clock_gettime(CLOCK_REALTIME, &tspec);
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end = tspec.tv_sec+1e-9*tspec.tv_nsec;
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printf("Elapsed Time: %f s\n", end-start);
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return 0;
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}
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unsigned char *create_image(int w, int h) {
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unsigned char *rv;
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return rv = malloc(w*h*3);
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}
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void set_pixel(unsigned char *img, int x, int y, unsigned char *color) {
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img[3*(x+y*width)+0] = color[0]; // Red
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img[3*(x+y*width)+1] = color[1]; // Green
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img[3*(x+y*width)+2] = color[2]; // Blue
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}
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void write_ppm(char *name, int w, int h, unsigned char *img) {
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FILE *out;
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if (!(out=fopen(name, "w"))) {
211+
fprintf(stderr, "Unable to open %s for writing\n", name);
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return;
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}
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fprintf(out, "P6\n%d %d\n255\n", width, height);
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fwrite(img, 3, w*h, out);
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fclose(out);
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}

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