public static double SolveB(double a, double x, double p, double q, double guess, double step, double lower, double upper)
{
Func <double, double> f;
if (p <= q)
{
f = b => Math2.Ibeta(a, b, x) - p;
}
else
{
f = b => Math2.Ibetac(a, b, x) - q;
}
#if EXTRA_DEBUG
Debug.WriteLine("IBetaInvB(a={0}, guess?={1}, x={2}) == p({3}), q({4}); range = [{5}, {6}]", a, guess, x, p, q, lower, upper);
#endif
RootResults r = RootFinder.Toms748Bracket(f, guess, step, FunctionShape.Unknown, lower, upper, _tol, Policies.MaxRootIterations);
if (r == null)
{
Policies.ReportRootNotFoundError("Invalid parameter in root solver");
return(double.NaN);
}
if (!r.Success)
{
Policies.ReportRootNotFoundError("Root not found after {0} iterations", r.Iterations);
return(double.NaN);
}
#if EXTRA_DEBUG
Debug.WriteLine("Result = {0}; Toms748 iterations: {1}", r.SolutionX, r.Iterations);
#endif
return(r.SolutionX);
}