text: public static double pv(double r, double n, double y, double f, boolean t) {double retval = 0;if (r == 0) {retval = -1*((n*y)+f);}else {double r1 = r + 1;retval =(( ( 1 - Math.pow(r1, n) ) / r ) * (t ? r1 : 1)  * y - f)/Math.pow(r1, n);}return retval;}