computes the incomplete gamma function.
double incgamma( double x, double a )
incomplete gamma function of x, a
EX1
void incgamma_ex1() { double a = 2, x = .5; double val = incgamma(x, a); printf("incgamma(%f, %f) = %f\n", x, a, val); }
incomplete_gamma, incbeta
origin.h