/*
* use R built-in root finder API :R_zeroin
*/
double solve(double b, double w)
{
// w == 0 means its really arcsinh
if (w == 0)
{
return(b);
}
// precision is the same as that of b
double tolerance = 2 * b * Double.Epsilon;
sfun_info param = new sfun_info()
{
b = b, w = w
};
// bracket the root
double d_lo = 0;
double d_hi = b;
int MaxIt = 20;
double d;
d = R_zeroin(d_lo, d_hi, logicle_fn, param, ref tolerance, ref MaxIt);
return(d);
}
// f(w,b) = 2 * (ln(d) - ln(b)) + w * (b + d)
double logicle_fn(double x, dynamic info)
{
sfun_info p = (sfun_info)info;
double B = 2 * (Math.Log(x) - Math.Log(p.b)) + p.w * (p.b + x);
return(B);
}
/*
* use R built-in root finder API :R_zeroin
*/
double solve(double b, double w)
{
// w == 0 means its really arcsinh
if (w == 0)
return b;
// precision is the same as that of b
double tolerance = 2 * b * Double.Epsilon;
sfun_info param = new sfun_info() { b = b, w = w };
// bracket the root
double d_lo = 0;
double d_hi = b;
int MaxIt = 20;
double d;
d = R_zeroin(d_lo, d_hi, logicle_fn, param, ref tolerance, ref MaxIt);
return d;
}
