double MothurFisher::lnbico(double n, double k){
try {
return(lnfact(n)-lnfact(k)-lnfact(n-k));
}catch(exception& e) {
m->errorOut(e, "MothurFisher", "lnbico");
exit(1);
}
}
static gdouble wigner (guint l, gint m1, gint m2, gdouble beta)
{
gdouble ret = 0.;
gint l_m_m1, l_p_m1, l_m_m2, l_p_m2, m1_m_m2;
gint k, kmin, kmax;
gdouble cb2, sb2, a;
g_assert (ABS (m1) <= ((gint) l));
g_assert (ABS (m2) <= ((gint) l));
l_m_m1 = l - m1;
l_p_m1 = l + m1;
l_m_m2 = l - m2;
l_p_m2 = l + m2;
m1_m_m2 = m1 - m2;
kmin = MAX (0, -m1_m_m2);
kmax = MIN (l_m_m1, l_p_m2);
if (kmin > kmax)
return ret;
aran_coefficient_bufferd_require (_lnfact, 2*l);
a = (lnfact (l_p_m1) + lnfact (l_m_m1) + lnfact (l_p_m2) +
lnfact (l_m_m2)) * 0.5;
cb2 = cos (beta * 0.5);
sb2 = sin (beta * 0.5);
for (k = kmin; k <= kmax; k++)
{
gdouble b = lnfact (k) + lnfact (l_m_m1 - k) + lnfact (l_p_m2 - k) +
lnfact (m1_m_m2 + k);
gdouble c = pow (cb2, l_m_m1 + l_p_m2 - 2 * k);
gdouble d = pow (sb2, m1_m_m2 + 2 * k);
ret += PHASE (m1_m_m2 + k) * exp (a - b) * c * d;
}
return ret;
}
double lnbico(int n, int k) {
return lnfact(n) - lnfact(k) - lnfact(n-k);
}
double bico(int n, int k) {
return floor(0.5 + exp(lnfact(n) - lnfact(k) - lnfact(n-k)));
}
float_t lnmultinomial::lnmultinomcoef(const count_t *s){
return lnfact(s[0]+s[1]+s[2]+s[3])-lnfact(s[0])-lnfact(s[1])-lnfact(s[2])-lnfact(s[3]);
}
