| public static ModPow ( int powerBase, int exp, int prime ) : int | ||
| powerBase | int | |
| exp | int | |
| prime | int | |
| return | int | |
public static Zp EvalutePolynomialAtPoint(IList <Zp> polynomial, Zp point)
{
int evaluation = 0;
for (int i = 0; i < polynomial.Count; i++)
{
evaluation += polynomial[i].Value * NumTheoryUtils.ModPow(point.Value, i, point.Prime);
}
return(new Zp(point.Prime, evaluation));
}
/// <param name="SamplePoint"> - the desired sampling point. </param>
/// <returns> the result of the polynom when replacing variable ("x") with the sampling point </returns>
public virtual Zp Sample(Zp SamplePoint)
{
if (Coefficients.Count == 0)
{
return(null);
}
/* The initialized sum is 0 */
var Sum = new Zp(CoefficinesFieldSize, 0);
for (int i = 0; i < Coefficients.Count; i++)
{
/* replace each "Ai*x^i" with "Ai*SamplePoint^i" */
var Xi = new Zp(CoefficinesFieldSize,
NumTheoryUtils.ModPow(SamplePoint.Value, i, CoefficinesFieldSize));
var Ai = new Zp(CoefficinesFieldSize, Coefficients[i].Value);
var AiXi = Xi.Mul(Ai);
/* Sum all these values(A0+A1X^1+...AnX^n) */
Sum = Sum.Add(AiXi);
}
return(Sum);
}
