/// <summary>
/// Multiply current Polynomial to anotherone.
/// </summary>
/// <returns>Result polynomial after multiply</returns>
internal Polynomial Multiply(Polynomial other)
{
if (Primitive != other.Primitive)
{
throw new ArgumentException("Polynomial cannot perform Multiply as they do not have same Primitive for GaloisField256");
}
if (IsMonomialZero || other.IsMonomialZero)
{
return(new Polynomial(GField, new int[] { 0 }));
}
int[] aCoefficients = Coefficients;
int aLength = aCoefficients.Length;
int[] bCoefficient = other.Coefficients;
int bLength = bCoefficient.Length;
int[] rCoefficients = new int[aLength + bLength - 1];
for (int aIndex = 0; aIndex < aLength; aIndex++)
{
int aCoeff = aCoefficients[aIndex];
for (int bIndex = 0; bIndex < bLength; bIndex++)
{
rCoefficients[aIndex + bIndex] =
GField.Addition(rCoefficients[aIndex + bIndex], GField.Product(aCoeff, bCoefficient[bIndex]));
}
}
return(new Polynomial(GField, rCoefficients));
}
internal Polynomial CoefficientXor(int[] smallerCoefficients, int[] largerCoefficients)
{
if (smallerCoefficients.Length > largerCoefficients.Length)
{
throw new ArgumentException("Can not perform CoefficientXor method as smaller Coefficients length is larger than larger one.");
}
int targetLength = largerCoefficients.Length;
int[] xorCoefficient = new int[targetLength];
int lengthDiff = largerCoefficients.Length - smallerCoefficients.Length;
Array.Copy(largerCoefficients, 0, xorCoefficient, 0, lengthDiff);
for (int index = lengthDiff; index < targetLength; index++)
{
xorCoefficient[index] = GField.Addition(largerCoefficients[index], smallerCoefficients[index - lengthDiff]);
}
return(new Polynomial(GField, xorCoefficient));
}