double pnl_sf_hyperg_U (double a, double b, double x) { double hu; int md; chgu_(&a, &b, &x, &hu, &md); return hu; }
/// Tricomi confluent hypergeometric functions. double tricomi_u(double a, double c, double x) { double hu; int md; chgu_(&a, &c, &x, &hu, &md); return hu; }