double logbino(int n, int k)
/* log n choose k */
{
double top, bot ;
top = logfac(n) ;
bot = logfac(n-k) + logfac(k) ;
return top-bot ;
}
// calculate the weights for the hermite polynomial
// at the roots
// using formula Abramowitz and Stegun chapter 25.4.46 p.890
void hermite_weight(long n, double * hroot, double * weights)
{
long i;
double hr2;
double nominator = exp(LOG2 * ( n-1.) + logfac(n)) * SQRTPI / (n*n);
for(i=0;i<n; i++)
{
hr2 = hermite(n-1, hroot[i]);
weights[i] = nominator / (hr2*hr2);
}
}
// calculate the weights for the hermite polynomial
// at the roots
// using formula Abramowitz and Stegun chapter 25.4.46 p.890
void
hermite_weight (long n, MYREAL *hroot, MYREAL *weights)
{
long i;
MYREAL hr2;
MYREAL nominator = EXP (LOG2 * (n - 1.) + logfac (n)) * SQRTPI / (n * n);
for (i = 0; i < n; i++)
{
hr2 = hermite (n - 1, hroot[i]);
weights[i] = nominator / (hr2 * hr2);
}
}