This function returns the natural logarithm of the gamma function.
double gammaln( double x )
the natural logarithm of the gamma function of x.
EX1
void gammaln_ex1() { double x = 17.; double val = gammaln(x); printf("gammaln(%f) = %f\n", x, val); double y = 17; double vy = gamma(y); double vvy = ln(vy); printf("val = %.lf, vvy = %.lf\n", val, vvy); }
origin.h