/*------------------------------------------------------------------*/
double getInitialCausalCoefficientMirrorOnBounds(double[] c, double z, double tolerance) {
double z1 = z, zn = Math.pow(z, c.length - 1);
double sum = c[0] + zn * c[c.length - 1];
int horizon = c.length;
if (0.0 < tolerance) {
horizon = 2 + (int) (Math.log(tolerance) / Math.log(Math.abs(z)));
horizon = (horizon < c.length) ? (horizon) : (c.length);
}
zn = zn * zn;
for (int n = 1; (n < (horizon - 1)); n++) {
zn = zn / z;
sum = sum + (z1 + zn) * c[n];
z1 = z1 * z;
}
return (sum / (1.0 - Math.pow(z, 2 * c.length - 2)));
} /* end getInitialCausalCoefficientMirrorOnBounds */
double rodbard(double x) {
// y = c*((a-x/(x-d))^(1/b)
// a=3.9, b=.88, c=712, d=44
double ex;
if (x == 0.0) ex = 5.0;
else ex = Math.exp(Math.log(x / 700.0) * 0.88);
double y = 3.9 - 44.0;
y = y / (1.0 + ex);
return y + 44.0;
}