view tests/pointset_test/genpoints2.c @ 496:8fb85fbcaba6 api-inversion

Mostly disentangle API from command-line binary.

Now audioDB.cpp doesn't need to be included in the library, because
nothing the library does creates an audioDB instance.  Hooray.  We can't
disentangle the other way, because there's still plenty in the
command-line binary that isn't implemented in terms of the API, so the
audioDB binary code needs to know naughty stuff about the library's
internals (e.g. what the file header looks like).

Remove liszt.o and sample.o from the library, even though they'll
probably make a reapparance soon (for scare-quoted values of "soon")

Remove cmdline.o and common.o from the library, not scheduled to make a
reapparence ever (hooray!).  Separate out the bits that are used in the
library -- locks and PointPairs -- into their own files.

#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <math.h>
#include <stdlib.h>
#include <stdio.h>

double randn();
double randbl();

/* genpoints count radius^2 */
int main(int argc, char *argv[]) {
  if (argc < 3) {
    fprintf(stderr, "usage: %s count radius^2 [dim]\n", argv[0]);
    exit(1);
  }
  long int count = strtol(argv[1], NULL, 0);
  double rsquared = strtod(argv[2], NULL);
  long int dim = 3;
  if(argc > 3)
    dim = strtol(argv[3], NULL, 0);
  
  // Generate *count* Gaussian Random vectors in R^*dim*
  // sitting on the *rdashed*-sphere

  srandom(time(NULL));

  int i,j;
  for (i = 0; i < count + 1; i++) {
    // Normed Gaussian random vectors are distributed uniformly on unit sphere
    double* coords = malloc(dim * sizeof(double));
    double nmsq = 0.0;

    for (j = 0; j < dim; j++){
      if(i < count)
	coords[j] = randn();
      else
	coords[j] = 0.0;
      nmsq += coords[j]*coords[j];
    }

    double nm2 = 0.0;
    if(i < count){
      nm2 = sqrt(rsquared/nmsq);
      // Place on rdash-sphere
      for (j = 0; j < dim; j++)
	coords[j] *= nm2;
    }
    // Translate to (0,0,...,1)
    coords[dim-1]+=1.0; 

    // Compute distance to (0,0,...,1)
    nmsq = 0.0;
    for (j = 0; j < dim-1; j++){
      nmsq += coords[j]*coords[j];
    }
    // Save last value to distance calulcation to query(0,0,...,1)
    double nth = coords[dim-1];
    // Output to ASCII terminal
    printf("(");
    for(j = 0; j < dim; j++)
      printf("%8.3f ", coords[j]);
    printf(") d = %8.3f\n", sqrt(nmsq + (nth-1)*(nth-1)));
    

    // Save single feature vector
    char name[40];
    if(i < count)
      snprintf(name, 39, i<10?"testfeature0%d":"testfeature%d", i);
    else
      snprintf(name, 39, "queryfeature");
    /* assumes $PWD is right */
    int fd = open(name, O_CREAT|O_TRUNC|O_WRONLY, S_IWUSR|S_IRUSR|S_IRGRP|S_IROTH);

    write(fd, &dim, sizeof(int));
    for(j = 0; j < dim; j++)
      write(fd, coords + j, sizeof(double));
    close(fd);

    free(coords);
  }
  exit(0);
}

// Genereate U[0,1]
double randbl(){
  return (   (double)rand() / ((double)(RAND_MAX)+(double)(1)) );
}

// Generate z ~ N(0,1)
double randn(){
// Box-Muller
  double x1, x2;
  do{
    x1 = randbl();
  } while (x1 == 0); // cannot take log of 0
  x2 = randbl();
  double z = sqrt(-2.0 * log(x1)) * cos(2.0 * M_PI * x2);
  return z;
}