view xthresh.c @ 404:1fb8bee777e5 api-inversion

Begin working towards inverting audioDB::insert() / audiodb_insert().

New data type audiodb_datum_t, roughly corresponding to a "track" in
current audioDB parlance; it contains exactly the feature information
and metadata to record.

New function audiodb_insert_datum() to insert one of these
audiodb_datum_t objects into the database; the intention is that not
only can insertion of feature files be implemented in terms of this
function, but that it will be a useful function in its own right,
callable perhaps from PD, Max/MSP, and/or a VAMP plugin.  This function
is complicated enough that it actually gets a comment.

Implement audioDB::insert() in terms of audiodb_insert_datum(), via a
wrapper which handles the slightly wacky error/non-error case of
attempting to insert features with a key that already exists in the
database.

Delete whole rafts of code.  We can't quite delete everything because
there's batchinsert / batchinsert_large_adb to sort out; the good news
is that the batchinsert operation can simply be implemented as a loop
around audiodb_insert_datum() without loss of efficiency.

(There's also a stray extra audiodb_insert() in libtests/0027/, found
through an earlier iteration of this patch.)

#include <gsl/gsl_sf.h>
#include <stdio.h>
#include <stdlib.h>
#include <math.h>

int main(int argc, char *argv[]) {
  if(argc != 4) {
    fprintf(stderr, "Wrong number of arguments: %d\n", argc);
    exit(1);
  }

  long int meanN = strtol(argv[1], NULL, 10);

  double d = strtod(argv[2], NULL);
  double sigma2 = strtod(argv[3], NULL);

  double logw = (2 / d) * gsl_sf_log(-gsl_sf_log(0.99));
  double logxthresh = gsl_sf_log(sigma2) + logw
    - (2 / d) * gsl_sf_log(meanN)
    - gsl_sf_log(d/2)
    - (2 / d) * gsl_sf_log(2 / d)
    + (2 / d) * gsl_sf_lngamma(d / 2);

  printf("w: %f\n", exp(logw));
  printf("x_thresh: %f\n", exp(logxthresh));
  exit(0);
}