Trasferito da en.wikipedia su Commons da Maksim.

//

Quest'opera è considerata software libero; può essere redistribuita e/o modificata secondo i termini GNU General Public License così come pubblicata dalla Free Software Foundation; sia la versione 2 della licenza, o (a tua scelta) qualsiasi versione successiva. Quest'opera viene distribuita nella speranza che sia utile, ma senza alcuna garanzia; nemmeno con la garanzia di viabilità sul mercato o di appropriatezza per un particolare fine. Per maggiori dettagli, vedi il testo originale in inglese della versione 2 e della versione 3 della GNU General Public License.http://www.gnu.org/licenses/gpl.htmlGPLGNU General Public Licensetruetrue

c src code
#include <stdio.h>
#include <stdlib.h>
#include <time.h>

#define PI 3.1415926535897932
#define TAU (PI * 2)
#define SQ2 1.4142135623730950
#define SQ3 1.7320508075688772
#define PHI 1.6180339887498948

#define SX 1111
#define SY 1111

//////////////////MAKE PRETTY PATTERNS HERE. DPOLY must be POLY differentiated.

#define POLY(z) z *z *z *z *z + (-1)
#define DPOLY(z) 5 * z *z *z *z

// #define POLY(z)  z*z*z*z*z*z*z*z*z + (-1)
// #define DPOLY(z) 9*z*z*z*z*z*z*z*z

// #define POLY(z)  z*z*z*z*z + (-3i) * z*z*z + (-5-2i) * z*z + (3) * z + (1)
// #define DPOLY(z) 5*z*z*z*z + (-3i) * 3*z*z + (-5-2i) * 2*z + (3) * 1

// #define POLY(z)  z*z*z*z*z*z + (2-4i) * z*z*z*z*z + (-1) * z + (2+4i)
// #define DPOLY(z) 6*z*z*z*z*z + (2-4i) * 5*z*z*z*z + (-1) * 1

// #define POLY(z)  z*z*z*z*z + (-1) * z + (-1)
// #define DPOLY(z) 5*z*z*z*z + (-1) * 1

// #define POLY(z)  z*z*z*z*z + (-1) - (cos(__imag__ z)+1i*sin(__imag__ z))*exp(__real__ z)
// #define DPOLY(z) 5*z*z*z*z -         (cos(__imag__z)+1i*sin(__imag__ z))*exp(__real__ z)

#define RSD 1923879

#define BPL ((SX * 3 + 3) & ~3)

void seedr(unsigned int);
unsigned int rnd();
unsigned int rndm(unsigned int);

unsigned char bhdr[54] = {0x42, 0x4D, 0x36, 0x00, 0x30, 0x00, 0x00, 0x00, 0x00,
                          0x00, 0x36, 0x00, 0x00, 0x00, 0x28, 0x00, 0x00, 0x00,
                          0x00, 0x04, 0x00, 0x00, 0x00, 0x04, 0x00, 0x00, 0x01,
                          0x00, 0x18, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
                          0x30, 0x00, 0x12, 0x0B, 0x00, 0x00, 0x12, 0x0B, 0x00,
                          0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00};

unsigned char po[BPL];

double gr[SY][SX][3];

void drawit();

int main(int a, char **b) {
  FILE *o;
  int x, y, c;
  double t;
  unsigned char *p; // fixed error due to conversion from unsigned char to char

  srand(time(0));
  drawit();

  p = bhdr + 2;
  *p++ = x = 54 + BPL * SY;
  *p++ = x >>= 8;
  *p++ = x >>= 8;
  *p = x >>= 8;
  p = bhdr + 18;
  *p++ = x = SX;
  *p++ = x >>= 8;
  *p++ = x >>= 8;
  *p++ = x >>= 8;
  *p++ = x = SY;
  *p++ = x >>= 8;
  *p++ = x >>= 8;
  *p = x >>= 8;

  if (!(o = fopen("newtroot.bmp", "wb"))) {
    fclose(o);
    printf("Couldn't open output file.\n");
    return (0);
  }

  fwrite(bhdr, 54, 1, o);

  for (x = SX * 3; x < BPL; ++x)
    po[x] = 0;

  for (y = SY - 1; ~y; --y) {
    for (x = 0, p = po; x < SX; ++x)
      for (c = 2; ~c; --c)
        *p++ = (t = gr[y][x][c]) <= 0 ? 0 : (t >= 1 ? 255 : t * 255);
    fwrite(po, BPL, 1, o);
  }

  fclose(o);
  return (0);
}

void drawit() {
  int x, y, c, n, bn, dx, dy, dz;
  unsigned int m, p;
  _Complex double z, w;
  double f, s;
  seedr(RSD);
  for (y = 0; y < SY; ++y)
    for (x = 0; x < SX; ++x) {
      z = (x * (10. / SX) - 5) - (y * (10. / SY) - 5) * 1i;
      w = POLY(z);

      for (f = s = 1; f > .01 && (__real__(w * ~w)) > .01;
           f *= .95, s = -s, w = POLY(z))
        z = z - w / (DPOLY(z));
      z = z - w / (DPOLY(z));

      for (n = 0; n < 10; ++n)
        z = z - (POLY(z)) / (DPOLY(z));

      z = f * (z * z) / (z * ~z);

      gr[y][x][0] = .5 * f /*+.02*s*f*/ + .24 * (__real__(z)) -
                    (SQ3 * .24) * (__imag__(z));
      gr[y][x][1] = .5 * f /*+.02*s*f*/ + .24 * (__real__(z)) +
                    (SQ3 * .24) * (__imag__(z));
      gr[y][x][2] = .5 * f /*+.02*s*f*/ - .48 * (__real__(z));
    }
}

unsigned int rseeda[624];
int rseedu;

void seedr(unsigned int s) {
  int n;
  rseedu = 624;
  rseeda[0] = s;
  for (n = 1; n < 624; ++n)
    rseeda[n] = s *= 69069u;
}

#define TEMPBLAH(x, y, z)                                                      \
  {                                                                            \
    v = (rseeda[x] & 0x80000000) | (rseeda[y] & 0x7fffffff);                   \
    rseeda[x] = rseeda[z] ^ (v >> 1) ^ (0x9908b0df & (0 - (v & 1)));           \
  }
void gennewr() {
  int n;
  unsigned int v;
  for (n = 0; n < 227; ++n)
    TEMPBLAH(n, n + 1, n + 397);
  for (; n < 623; ++n)
    TEMPBLAH(n, n + 1, n - 227);
  TEMPBLAH(623, 0, 396);
  rseedu = 0;
}
#undef TEMPBLAH

unsigned int rnd() {
  if (rseedu >= 624)
    gennewr();
  unsigned int v = rseeda[rseedu++];
  v ^= v >> 11;
  v ^= (v << 7) & 0x9d2c5680;
  v ^= (v << 15) & 0xefc60000;
  v ^= v >> 18;
  return (v);
}

unsigned int rndm(unsigned int m) {
  unsigned int v, c = (0u - m) / m;
  while ((v = rnd()) / m > c)
    ;
  return (v % m);
}




date/time
username
edit summary


13:01, 12 November 2005
en:User:129.177.30.18
(Fix bug: change x over [0, SY] to x over [0, SY]. Would only be a problem if SX != SY.)


05:07, 14 November 2004
en:User:Cyp
(+Source)


05:06, 14 November 2004
en:User:Cyp
(Finding roots with "Newton's method")


Registro originale del caricamento
Legend: (cur) = this is the current file, (del) = delete this old version, (rev) = revert to this old version.

Click on date to download the file or see the image uploaded on that date.
* (del) (cur) 05:06, 14 November 2004 . . en:User:Cyp Cyp ( en:User_talk:Cyp Talk) . . 1111x1111 (527065 bytes) (Finding roots with "Newton's method") 

Further descriptions on en:Newton fractal and de:Newton-Fraktal.