double dirmult(double *pp, int *aa, int len)
{
int t, i, m ;
double y1, y2, ysum ;
double top, bot ;
m = len ;
t = intsum(aa,m) ;
if (t < 1) return 0.0 ;
top = bot = 0.0 ;
ysum = asum(pp,m) ;
for (i=0; i<m; i++) {
top += lgamma(pp[i] + (double) aa[i]) ;
bot += lgamma(pp[i]) ;
}
top += lgamma(ysum) ;
bot += lgamma(ysum + (double) t) ;
y1 = top-bot ;
return y1 -y2 ;
}
int dekodeitb(int *xx, int kode, int len, int base)
{
int i, t ;
t = kode ;
for (i=len-1; i>=0; --i) {
xx[i] = t % base ;
t /= base ;
}
return intsum(xx, len) ; // weight
}
int dekodeitbb(int *xx, int kode, int len, int *baselist)
{
// return weight
int i, t, base ;
t = kode ;
for (i=len-1; i>=0; --i) {
base = baselist[i] ;
xx[i] = t % base ;
t /= base ;
}
return intsum(xx, len) ;
}
double logmultinom(int *cc, int n)
/* log multinomial */
{
int t, k, i ;
double y, ytot ;
if (n<=1) return 0.0 ;
t = intsum(cc, n) ;
if (t==0) return 0.0 ;
ytot = 0 ;
for (i=0; i<n-1; i++) {
k = cc[i] ;
y = logbino(t,k) ;
ytot += y ;
t -= k ;
}
return ytot ;
}
