/* Function: esl_hxp_Sample()
*
* Purpose: Sample a random variate x from a hyperexponential <h>,
* given random number source <r>.
*/
double
esl_hxp_Sample(ESL_RANDOMNESS *r, ESL_HYPEREXP *h)
{
int k;
k = esl_rnd_DChoose(r, h->q, h->K);
return esl_exp_Sample(r, h->mu, h->lambda[k]);
}
/* Function: esl_mixgev_Sample()
*
* Purpose: Sample a random variate x from a mixture GEV <mg>,
* given random number source <r>.
*/
double
esl_mixgev_Sample(ESL_RANDOMNESS *r, ESL_MIXGEV *mg)
{
int k;
k = esl_rnd_DChoose(r, mg->q, mg->K);
return esl_gev_Sample(r, mg->mu[k], mg->lambda[k], mg->alpha[k]);
}
/* The DChoose() and FChoose() unit tests.
*/
static void
utest_choose(ESL_RANDOMNESS *r, int n, int nbins, int be_verbose)
{
double *pd = NULL;
float *pf = NULL;
int *ct = NULL;
int i;
double X2, diff, exp, X2p;
if ((pd = malloc(sizeof(double) * nbins)) == NULL) esl_fatal("malloc failed");
if ((pf = malloc(sizeof(float) * nbins)) == NULL) esl_fatal("malloc failed");
if ((ct = malloc(sizeof(int) * nbins)) == NULL) esl_fatal("malloc failed");
/* Sample a random multinomial probability vector. */
if (esl_dirichlet_DSampleUniform(r, nbins, pd) != eslOK) esl_fatal("dirichlet sample failed");
esl_vec_D2F(pd, nbins, pf);
/* Sample observed counts using DChoose(). */
esl_vec_ISet(ct, nbins, 0);
for (i = 0; i < n; i++)
ct[esl_rnd_DChoose(r, pd, nbins)]++;
/* X^2 test on those observed counts. */
for (X2 = 0., i=0; i < nbins; i++) {
exp = (double) n * pd[i];
diff = (double) ct[i] - exp;
X2 += diff*diff/exp;
}
if (esl_stats_ChiSquaredTest(nbins, X2, &X2p) != eslOK) esl_fatal("chi square eval failed");
if (be_verbose) printf("DChoose(): \t%g\n", X2p);
if (X2p < 0.01) esl_fatal("chi squared test failed");
/* Repeat above for FChoose(). */
esl_vec_ISet(ct, nbins, 0);
for (i = 0; i < n; i++)
ct[esl_rnd_FChoose(r, pf, nbins)]++;
for (X2 = 0., i=0; i < nbins; i++) {
exp = (double) n * pd[i];
diff = (double) ct[i] - exp;
X2 += diff*diff/exp;
}
if (esl_stats_ChiSquaredTest(nbins, X2, &X2p) != eslOK) esl_fatal("chi square eval failed");
if (be_verbose) printf("FChoose(): \t%g\n", X2p);
if (X2p < 0.01) esl_fatal("chi squared test failed");
free(pd);
free(pf);
free(ct);
return;
}
