private static double[] GradF(double[] x, Function F)
{
int n = x.Length;
double[] grad = new double[n];
for (int i = 0; i < n; i++)
{
grad[i] = FDiff(i, F)(x);
}
return(grad);
}
private static double[,] GessF(double[] x, Function F)
{
int n = x.Length;
double[,] gess = new double[n, n];
for (int i = 0; i < n; i++)
{
for (int j = 0; j < n; j++)
{
gess[i, j] = FDiff(j, FDiff(i, F))(x);
}
}
return(gess);
}