music2.c: For producing chaotic music with note durations

This program is an attempt at producing music with not only pitches but non-arbitrary note durations. Its operation is the same as music.c, except for the addition of a note duration handler. The durations come from any of the system's variables, and are quantized down to four binarily weighted levels corresponding to eighth, quarter, half and whole note durations.

/*
 * Lorenz attractor chaotic music generator
 * $Id$
 * Mike Andrews
 *
 */ 

#include <stdio.h>
#include <stdlib.h>
#include <math.h>

#define DATASIZE  100                /* Number of data points in output  */
#define TIMESTEP  0.0001             /* Numerical timestep for dt        */
#define XSCALE    0.65               /* Appropriate scaling factors for  */
#define YSCALE    0.65               /*   each axis.                     */
#define ZSCALE    0.65
#define TSCALE    20                 /* Scaling factor for the time axis */
#define QUANTIZE  3                  /* Quantization interval for the
                                        time axis */

void main()
{
    double x1, y1, z1, x, y, z, t, dt, dx, dy, dz, initial;
    int    xdat[DATASIZE], ydat[DATASIZE], zdat[DATASIZE];
    int    dxdat[DATASIZE], dydat[DATASIZE], dzdat[DATASIZE];
    int    qindex=0, hindex=0, eindex=0, windex=0;
    int    duration[DATASIZE], melody[DATASIZE], i=0;
    int    tp=0, tpo=-1, stuff[4];
    long int tmp=0;

    FILE  *song;

    song=fopen("output", "w");

    printf("\nEnter initial conditions (x1=y1=z1=t= ?):");
    scanf("%lf", &initial);
    x1=(y1=(z1=(t=initial)));              /* Set initial conditions */
    melody[i]=(duration[i]=0);

    dt=TIMESTEP;

    while(tp<((DATASIZE*QUANTIZE)-1))
    {
        x=x1 + ( -10.0*x1  + 10.0*y1    ) * dt;
        y=y1 + ( 28.0*x1   - y1 - x1*z1 ) * dt;
        z=z1 + ( -(8/3)*z1 + x1*y1      ) * dt;
        t=t  +                              dt;
        dx= -10.0*x  + 10.0*y;
        dy=  28.0*x  - y      - x*z;
        dz= -(8/3)*z + x*y;


        tp=(int)floor(TSCALE*t);
        
        x1=x;
        y1=y;
        z1=z;
       
        if ((!(tp%QUANTIZE))&&(tp!=tpo))
          {
            tpo=tp;
            xdat[i]=(int)floor(XSCALE*x);
            ydat[i]=(int)floor(YSCALE*y);
            zdat[i]=(int)floor(ZSCALE*z);
            dxdat[i]= (int)floor(dx);
            dydat[i]= (int)floor(dy);
            dzdat[i]= (int)floor(dz);
            i++;
          }
    }
    
    for (i=0; i<DATASIZE; i++)
    {
        melody[i]=xdat[i];
        duration[i]=1;
    }

    eindex=0;
    qindex=1;
    hindex=2;
    windex=3;

    for (i=0; i<4; i++) stuff[i]=0;   /* Stylistically, set
                                         probabilities in this order:
                                         eighth, quarter, half, whole
                                         */ 
    for (i=0; i<DATASIZE; i++) stuff[duration[i]]++;
    tmp=0;
    for (i=0; i<4; i++)
        if (stuff[i]>stuff[tmp]) tmp=i;
    eindex=tmp;
    stuff[tmp]=-1;
    tmp=0;
    for (i=0; i<4; i++)
        if (stuff[i]>stuff[tmp]) tmp=i;
    qindex=tmp;
    stuff[tmp]=-1;
    tmp=0;
    for (i=0; i<4; i++)
        if (stuff[i]>stuff[tmp]) tmp=i;
    hindex=tmp;
    stuff[tmp]=-1;
    tmp=0;
    for (i=0; i<4; i++)
        if (stuff[i]>stuff[tmp]) tmp=i;
    windex=tmp;
    tmp=0;

    for (i=0; i<DATASIZE; i++)
    {
        if (duration[i]==eindex) duration[i]=1;
        else if (duration[i]==qindex) duration[i]=2;
        else if (duration[i]==hindex) duration[i]=4;
        else if (duration[i]==windex) duration[i]=8;
        fprintf(song, "%d %d\n", tmp, melody[i]);
        tmp+=duration[i];
    }

    fclose(song);
}