/// <summary>
/// Get value of preimage by value of image
/// </summary>
/// <param name="p">Value of image</param>
/// <param name="n">Degree of interpolation polynome</param>
/// <param name="table">Table set function</param>
/// <returns>Value of preimage</returns>
public static double Preimage_II(double p, int n, ref double[,] table)
{
var m = table.GetLength(0) - 1;
var a = table[0, 0];
var b = table[m, 0];
if (Math.Abs(Lab2.Lagrange(a, n, ref table) - p) < Eps)
{
return(a);
}
if (Math.Abs(Lab2.Lagrange(b, n, ref table) - p) < Eps)
{
return(b);
}
var mid = 0.0;
while (Math.Abs(b - a) > Eps)
{
mid = (b + a) / 2;
if ((Lab2.Lagrange(a, n, ref table) - p) *
(Lab2.Lagrange(mid, n, ref table) - p) < 0)
{
b = mid;
}
else
{
a = mid;
}
}
return(mid);
}
/// <summary>
/// Get value of preimage by value of image
/// </summary>
/// <param name="p">Value of image</param>
/// <param name="n">Degree of interpolation polynome</param>
/// <param name="table">Table set function</param>
/// <returns>Value of preimage</returns>
public static double Preimage_I(double p, int n, ref double[,] table)
{
var swappedTable = Tools.Table.SwapColumns(table);
return(Lab2.Lagrange(p, n, ref swappedTable));
}