annotate hmm/hmm.h @ 298:255e431ae3d4

* Key detector: when returning key strengths, use the peak value of the
  three underlying chromagram correlations (from 36-bin chromagram)
  corresponding to each key, instead of the mean.
  Rationale: This is the same method as used when returning the key value,
  and it's nice to have the same results in both returned value and plot.
  The peak performed better than the sum with a simple test set of triads,
  so it seems reasonable to change the plot to match the key output rather
  than the other way around.

* FFT: kiss_fftr returns only the non-conjugate bins, synthesise the rest
  rather than leaving them (perhaps dangerously) undefined.  Fixes an
  uninitialised data error in chromagram that could cause garbage results
  from key detector.

* Constant Q: remove precalculated values again, I reckon they're not
  proving such a good tradeoff.

#ifndef _HMM_H
#define _HMM_H

#ifdef __cplusplus
extern "C" {
#endif

/*
 *  hmm.h
 *  soundbite
 *
 *  Created by Mark Levy on 12/02/2006.
 *  Copyright 2006 Centre for Digital Music, Queen Mary, University of London. All rights reserved.
 *
 */

#ifndef PI    
#define PI 3.14159265358979323846264338327950288
#endif 

typedef struct _model_t {
	int N;			/* number of states */
	double* p0;		/* initial probs */
	double** a;		/* transition probs */
	int L;			/* dimensionality of data */
	double** mu;	/* state means */
	double** cov;	/* covariance, tied between all states */
} model_t;

void hmm_train(double** x, int T, model_t* model);							/* with scaling */
void forward_backwards(double*** xi, double** gamma, double* loglik, double* loglik1, double* loglik2, int iter, 
					   int N, int T, double* p0, double** a, double** b);
void baum_welch(double* p0, double** a, double** mu, double** cov, int N, int T, int L, double** x, double*** xi, double** gamma);
void viterbi_decode(double** x, int T, model_t* model, int* q);				/* using logs */
model_t* hmm_init(double** x, int T, int L, int N);
void hmm_close(model_t* model);
void invert(double** cov, int L, double** icov, double* detcov);			/* uses LAPACK (included with Mac OSX) */
double gauss(double* x, int L, double* mu, double** icov, double detcov, double* y, double* z);
double loggauss(double* x, int L, double* mu, double** icov, double detcov, double* y, double* z);
void hmm_print(model_t* model);

#ifdef __cplusplus
}
#endif

#endif