/* constantHMM -
* Initialises an HMM with constant transition log probabilities.
*/
void constantHMM(Hmm *m, int upper_triangular)
{ int u, v;
zeroHMM(m);
for (u = 0; u<m->uu; u++)
{ VECTOR(m->logB)[u] = 0;
for (v = upper_triangular?u:0; v<m->uu; v++) MATRIX(m->logA)[u][v] = 0;}
normaliseHMM(m, upper_triangular);}
/* randomiseHMM -
* Initialises an HMM with normalised random transition log probabilities.
*/
void randomiseHMM(Hmm *m, int upper_triangular)
{ int u, v;
zeroHMM(m);
for (u = 0; u<m->uu; u++)
{ VECTOR(m->logB)[u] = my_log(RANDOM);
for (v = upper_triangular?u:0; v<m->uu; v++)
{ MATRIX(m->logA)[u][v] = my_log(RANDOM);}}
normaliseHMM(m, upper_triangular);}
/* Add noise to m */
void noiseHMM(Hmm *m, int upper_triangular, Real delta){
int u, v;
for (u = 0; u < m->uu; u ++){
VECTOR(m->logB)[u] = add_exp(VECTOR(m->logB)[u], my_log(delta * RANDOM));
for (v = (upper_triangular? u: 0); v < m->uu; v ++){
MATRIX(m->logA)[u][v] = add_exp(MATRIX(m->logA)[u][v], my_log(delta * RANDOM));
}
}
normaliseHMM(m, upper_triangular);
}
void smoothHMM(Hmm *m, int upper_triangular, Real eps){
int u, v;
for (u = 0; u < m->uu; u ++){
if (VECTOR(m->logB)[u] == NEGATIVE_INFINITY)
VECTOR(m->logB)[u] = my_log(eps);
for (v = (upper_triangular? u: 0); v < m->uu; v ++)
if (MATRIX(m->logA)[u][v] == NEGATIVE_INFINITY)
MATRIX(m->logA)[u][v] = my_log(eps);
}
normaliseHMM(m, upper_triangular);
}
