public double[,] BuildInverseFDistributionTable(
double I0, int nu1Max, int nu2Max, int iPoints,
out int valuesRequested, out int valuesFound)
{
double[,] table = new double[nu1Max + 1, nu2Max + 1];
IxPoint ixp;
IXPointComparerIx compareIx = new IXPointComparerIx();
valuesRequested = nu1Max * nu2Max;
valuesFound = 0;
for (int nu1 = 1; nu1 <= nu1Max; nu1++)
{
for (int nu2 = 1; nu2 <= nu2Max; nu2++)
{
table[nu1, nu2] = double.NaN;
}
}
for (int nu2 = 1; nu2 <= nu2Max; nu2++)
{
double t = dis.InversetDistribution(1 - I0, nu2);
table[1, nu2] = t * t;
valuesFound++;
}
Search(I0, nu1Max, nu2Max, iPoints, ref table, ref valuesFound,
f.IncompleteBetaFunctionCF1);
if (valuesFound == valuesRequested)
{
return(table);
}
Search(I0, nu1Max, nu2Max, iPoints, ref table, ref valuesFound,
f.IncompleteBetaFunctionIntegration);
return(table);
}
private void Search(
double I0, int nu1Max, int nu2Max, int iPoints,
ref double[,] table, ref int valuesFound,
Func <double, double, double, double, double> incompleteBeta)
{
double x;
double Ix = 0, Ix0 = 0, Ix1 = 0, y = 0, x0 = 0, x1 = 0;
double slope = 0, inter = 0;
IxPoint ixp;
IXPointComparerIx compareIx = new IXPointComparerIx();
for (int nu1 = 1; nu1 <= nu1Max; nu1++)
{
double b = 0.5 * nu1;
for (int nu2 = 1; nu2 <= nu2Max; nu2++)
{
if (double.IsNaN(table[nu1, nu2]))
{
bool found = false;
double a = 0.5 * nu2, m = 1.0 / iPoints;
List <IxPoint> list = new List <IxPoint>();
for (int k = 0; k < iPoints; k++)
{
x = m * k;
Ix = incompleteBeta(x, a, b, 1.0e-5);
ixp = new IxPoint(Ix, x, nu1, nu2);
list.Add(ixp);
}
list.Sort(compareIx);
for (int i = 0; !found && i < list.Count - 1; i++)
{
ixp = list[i];
Ix0 = ixp.Ix;
x0 = ixp.X;
ixp = list[i + 1];
Ix1 = ixp.Ix;
x1 = ixp.X;
found =
(Ix0 != double.NaN && Ix1 != double.NaN) &&
(I0 >= Ix0 && I0 <= Ix1);
}
if (found)
{
// linear interpolation
slope = (Ix1 - Ix0) / (x1 - x0);
inter = Ix0 - slope * x0;
y = (I0 - inter) / slope;
y = Convertx(y, nu1, nu2);
if (y < 0)
{
y = double.NaN;
}
else
{
valuesFound++;
}
}
else
{
y = double.NaN;
}
table[nu1, nu2] = y;
}
}
}
}
