#include <atomic>
#include <cmath>
#include <cstdint>
#include <cstdio>
#include <vector>
#include <algorithm>
#include <mpfr.h>
#include <omp.h>
using std::vector;
using std::min;
const char * CENTER_RE = "-1.028457781372052547774824579171003431968291180173";
const char * CENTER_IM = "0.361463930751890432883338309925137437795829478445";
const char * VIEW_SIZE = "1.54e-44";
const int WIDTH = 10000;
const int HEIGHT = 10000;
const int AA = 8;
const int MAX_ITER = 50000;
const double ESCAPE_RADIUS_SQUARED = 50000.0;
const int PALETTE_FRAME = 155;
const char * OUTPUT_FILE = "Mandelbrot Set Image 113.bmp";
const mpfr_prec_t PRECISION_BITS = 1000;
const int REF_SIZE = MAX_ITER + 200;
struct Complex {
double re;
double im;
};
#pragma pack(push, 1)
struct BMPHeader {
uint16_t type{0x4D42};
uint32_t size{0};
uint32_t reserved{0};
uint32_t offBits{54};
uint32_t structSize{40};
int32_t width{0};
int32_t height{0};
uint16_t planes{1};
uint16_t bitCount{24};
uint32_t compression{0};
uint32_t sizeImage{0};
int32_t xPixelsPerMeter{2834};
int32_t yPixelsPerMeter{2834};
uint32_t colorsUsed{0};
uint32_t colorsImportant{0};
};
#pragma pack(pop)
int main() {
const double startTime = omp_get_wtime();
const long rawWidth = static_cast<long>(WIDTH) * AA;
const long rawHeight = static_cast<long>(HEIGHT) * AA;
mpfr_t centerRe, centerIm, zReMp, zImMp, tmp1, tmp2, viewSizeMp;
mpfr_inits2(PRECISION_BITS, centerRe, centerIm, zReMp, zImMp, tmp1, tmp2, viewSizeMp, static_cast<mpfr_ptr>(nullptr));
mpfr_set_str(centerRe, CENTER_RE, 10, MPFR_RNDN);
mpfr_set_str(centerIm, CENTER_IM, 10, MPFR_RNDN);
mpfr_set_str(viewSizeMp, VIEW_SIZE, 10, MPFR_RNDN);
const double sampleStep = mpfr_get_d(viewSizeMp, MPFR_RNDN) / rawWidth;
vector<Complex> referenceOrbit;
referenceOrbit.reserve(REF_SIZE);
mpfr_set_ui(zReMp, 0, MPFR_RNDN);
mpfr_set_ui(zImMp, 0, MPFR_RNDN);
for (int iter = 0; iter < REF_SIZE - 1; ++iter) {
Complex z{mpfr_get_d(zReMp, MPFR_RNDN), mpfr_get_d(zImMp, MPFR_RNDN)};
referenceOrbit.push_back(z);
if (z.re * z.re + z.im * z.im > ESCAPE_RADIUS_SQUARED) {
break;
}
mpfr_mul(tmp1, zReMp, zImMp, MPFR_RNDN);
mpfr_sqr(tmp2, zReMp, MPFR_RNDN);
mpfr_sqr(zReMp, zImMp, MPFR_RNDN);
mpfr_sub(zReMp, tmp2, zReMp, MPFR_RNDN);
mpfr_add(zReMp, zReMp, centerRe, MPFR_RNDN);
mpfr_mul_2ui(tmp1, tmp1, 1, MPFR_RNDN);
mpfr_add(zImMp, tmp1, centerIm, MPFR_RNDN);
}
const int referenceLength = static_cast<int>(referenceOrbit.size());
mpfr_clears(centerRe, centerIm, zReMp, zImMp, tmp1, tmp2, viewSizeMp, static_cast<mpfr_ptr>(nullptr));
std::fprintf(stderr, "Reference orbit: %d points\n", referenceLength);
std::fprintf(stderr, "Precomputing skip100 matrices...\n");
vector<Complex> coeff_A(REF_SIZE, {1.0, 0.0});
vector<Complex> coeff_B(REF_SIZE, {0.0, 0.0});
vector<double> rad_R(REF_SIZE, 2.0);
vector<double> aS_squared(REF_SIZE, 0.0);
for (int i = 0; i < referenceLength; ++i) {
double r2 = referenceOrbit[i].re * referenceOrbit[i].re + referenceOrbit[i].im * referenceOrbit[i].im;
aS_squared[i] = (r2 < ESCAPE_RADIUS_SQUARED) ? r2 : 0.0;
}
const int loop_limit = min(static_cast<int>(MAX_ITER), referenceLength - 105);
#pragma omp parallel for
for (int i = 0; i < loop_limit; ++i) {
double min_r2 = ESCAPE_RADIUS_SQUARED;
for (int k = 0; k < 100; ++k) {
if (i + k >= referenceLength) break;
if (aS_squared[i + k] < min_r2) min_r2 = aS_squared[i + k];
}
rad_R[i] = std::sqrt(min_r2);
for (int k = 0; k < 100; ++k) {
if (i + k >= referenceLength) break;
double r_re = referenceOrbit[i + k].re;
double r_im = referenceOrbit[i + k].im;
double next_A_re = 2.0 * (r_re * coeff_A[i].re - r_im * coeff_A[i].im);
double next_A_im = 2.0 * (r_re * coeff_A[i].im + r_im * coeff_A[i].re);
double next_B_re = 2.0 * (r_re * coeff_B[i].re - r_im * coeff_B[i].im) + 1.0;
double next_B_im = 2.0 * (r_re * coeff_B[i].im + r_im * coeff_B[i].re);
coeff_A[i].re = next_A_re; coeff_A[i].im = next_A_im;
coeff_B[i].re = next_B_re; coeff_B[i].im = next_B_im;
}
}
const double PI = 3.14159265358979323846;
uint8_t palette[256][3];
for (int i = 0; i < 255; ++i) {
palette[i][0] = static_cast<uint8_t>(std::lround(127.0 + 127.0 * std::cos(2.0 * PI * i / 255.0)));
palette[i][1] = static_cast<uint8_t>(std::lround(127.0 + 127.0 * std::sin(2.0 * PI * i / 255.0)));
palette[i][2] = palette[i][1];
}
palette[255][0] = 255; palette[255][1] = 255; palette[255][2] = 255;
const int rowBytes = (WIDTH * 3 + 3) & ~3;
vector<uint8_t> image(static_cast<size_t>(rowBytes) * HEIGHT, 0);
std::atomic<int> completedRows{0};
const Complex * reference = referenceOrbit.data();
#pragma omp parallel for schedule(dynamic)
for (int y = 0; y < HEIGHT; ++y) {
uint8_t * row = image.data() + static_cast<size_t>(y) * rowBytes;
for (int x = 0; x < WIDTH; ++x) {
unsigned blueSum = 0; unsigned greenSum = 0; unsigned redSum = 0;
for (int sampleY = 0; sampleY < AA; ++sampleY) {
const double deltaCIm = (static_cast<long>(y) * AA + sampleY - rawHeight / 2) * sampleStep;
for (int sampleX = 0; sampleX < AA; ++sampleX) {
const double deltaCRe = (static_cast<long>(x) * AA + sampleX - rawWidth / 2) * sampleStep;
double deltaRe = 0.0; double deltaIm = 0.0;
double zRe = 0.0; double zIm = 0.0;
int referenceIndex = 0;
int iter = 0;
while (iter < MAX_ITER) {
if (zRe * zRe + zIm * zIm >= ESCAPE_RADIUS_SQUARED) {
break;
}
double eps_abs2 = deltaRe * deltaRe + deltaIm * deltaIm;
double limit_r2 = 1e-30 * rad_R[referenceIndex] * rad_R[referenceIndex];
if (eps_abs2 < limit_r2 && (referenceIndex + 100 < loop_limit) && (iter + 100 < MAX_ITER)) {
double backup_deltaRe = deltaRe; double backup_deltaIm = deltaIm;
int backup_refIdx = referenceIndex; int backup_iter = iter;
double next_eps_re = (coeff_A[referenceIndex].re * deltaRe - coeff_A[referenceIndex].im * deltaIm) + 
(coeff_B[referenceIndex].re * deltaCRe - coeff_B[referenceIndex].im * deltaCIm);
double next_eps_im = (coeff_A[referenceIndex].re * deltaIm + coeff_A[referenceIndex].im * deltaRe) + 
(coeff_B[referenceIndex].re * deltaCIm + coeff_B[referenceIndex].im * deltaCRe);
deltaRe = next_eps_re; deltaIm = next_eps_im;
referenceIndex += 100; iter += 100;
zRe = reference[referenceIndex].re + deltaRe;
zIm = reference[referenceIndex].im + deltaIm;
if (zRe * zRe + zIm * zIm >= ESCAPE_RADIUS_SQUARED) {
deltaRe = backup_deltaRe; deltaIm = backup_deltaIm;
referenceIndex = backup_refIdx; iter = backup_iter;
} else {
continue; 
}
}
const double a = 2.0 * reference[referenceIndex].re + deltaRe;
const double b = 2.0 * reference[referenceIndex].im + deltaIm;
const double nextDeltaRe = a * deltaRe - b * deltaIm + deltaCRe;
deltaIm = a * deltaIm + b * deltaRe + deltaCIm;
deltaRe = nextDeltaRe;
++referenceIndex; ++iter;
zRe = reference[referenceIndex].re + deltaRe;
zIm = reference[referenceIndex].im + deltaIm;
if (zRe * zRe + zIm * zIm < deltaRe * deltaRe + deltaIm * deltaIm || referenceIndex >= loop_limit) {
deltaRe = zRe; deltaIm = zIm; referenceIndex = 0;
}
}
const int remaining = MAX_ITER - iter;
const uint8_t colorIndex = (remaining == 0) ? 255 : static_cast<uint8_t>(remaining % 254);
const int paletteIndex = (colorIndex == 255) ? 255 : (colorIndex - PALETTE_FRAME + 255) % 255;
blueSum += palette[paletteIndex][0];
greenSum += palette[paletteIndex][1];
redSum += palette[paletteIndex][2];
}
}
const int samples = AA * AA;
row[x * 3 + 0] = static_cast<uint8_t>(blueSum / samples);
row[x * 3 + 1] = static_cast<uint8_t>(greenSum / samples);
row[x * 3 + 2] = static_cast<uint8_t>(redSum / samples);
}
const int done = ++completedRows;
if (done % 50 == 0 || done == HEIGHT) {
std::fprintf(stderr, "\rProgress: %d/%d rows (%.1f%%)", done, HEIGHT, 100.0 * done / HEIGHT);
}
}
BMPHeader header;
header.width = WIDTH; header.height = HEIGHT;
header.sizeImage = static_cast<uint32_t>(image.size());
header.size = header.sizeImage + 54;
FILE * file = std::fopen(OUTPUT_FILE, "wb");
if (!file) { std::perror(OUTPUT_FILE); return 1; }
std::fwrite(&header, sizeof(header), 1, file);
std::fwrite(image.data(), 1, image.size(), file);
std::fclose(file);
std::fprintf(stderr, "\nDone! Saved to %s in %.2f seconds.\n", OUTPUT_FILE, omp_get_wtime() - startTime);
return 0;
}