/// <summary>
/// divide current polynomial by "other"
/// </summary>
/// <returns>Result polynomial after divide</returns>
internal PolyDivideStruct Divide(Polynomial other)
{
if (this.Primitive != other.Primitive)
{
throw new ArgumentException("Polynomial can not perform Devide as they don't have same Primitive for GaloisField256");
}
if (other.isMonomialZero)
{
throw new ArgumentException("Can not devide by Polynomial Zero");
}
//this devide by other = a devide by b
int aLength = this.Coefficients.Length;
//We will make change to aCoefficient. It will return as remainder
int[] aCoefficients = new int[aLength];
Array.Copy(this.Coefficients, 0, aCoefficients, 0, aLength);
int bLength = other.Coefficients.Length;
if (aLength < bLength)
{
return(new PolyDivideStruct(new Polynomial(this.GField, new int[] { 0 }), this));
}
else
{
//quotient coefficients
//qLastIndex = alength - blength qlength = qLastIndex + 1
int[] qCoefficients = new int[(aLength - bLength) + 1];
//Denominator
int otherLeadingTerm = other.GetCoefficient(other.Degree);
int inverseOtherLeadingTerm = this.GField.inverse(otherLeadingTerm);
for (int aIndex = 0; aIndex <= aLength - bLength; aIndex++)
{
if (aCoefficients[aIndex] != 0)
{
int aScalar = this.GField.Product(inverseOtherLeadingTerm, aCoefficients[aIndex]);
Polynomial term = other.MultiplyScalar(aScalar);
qCoefficients[aIndex] = aScalar;
int[] bCoefficient = term.Coefficients;
if (bCoefficient[0] != 0)
{
for (int bIndex = 0; bIndex < bLength; bIndex++)
{
aCoefficients[aIndex + bIndex] = this.GField.Subtraction(aCoefficients[aIndex + bIndex], bCoefficient[bIndex]);
}
}
}
}
return(new PolyDivideStruct(new Polynomial(this.GField, qCoefficients),
new Polynomial(this.GField, aCoefficients)));
}
}
/// <summary>
/// divide current polynomial by "other"
/// </summary>
/// <returns>Result polynomial after divide</returns>
internal PolyDivideStruct Divide(Polynomial other)
{
if(this.Primitive != other.Primitive)
{
throw new ArgumentException("Polynomial can not perform Devide as they don't have same Primitive for GaloisField256");
}
if(other.isMonomialZero)
{
throw new ArgumentException("Can not devide by Polynomial Zero");
}
//this devide by other = a devide by b
int aLength = this.Coefficients.Length;
//We will make change to aCoefficient. It will return as remainder
int[] aCoefficients = new int[aLength];
Array.Copy(this.Coefficients, 0, aCoefficients, 0, aLength);
int bLength = other.Coefficients.Length;
if(aLength < bLength)
return new PolyDivideStruct(new Polynomial(this.GField, new int[]{0}), this);
else
{
//quotient coefficients
//qLastIndex = alength - blength qlength = qLastIndex + 1
int[] qCoefficients = new int[( aLength - bLength ) + 1];
//Denominator
int otherLeadingTerm = other.GetCoefficient(other.Degree);
int inverseOtherLeadingTerm = this.GField.inverse(otherLeadingTerm);
for(int aIndex = 0; aIndex <= aLength - bLength; aIndex++)
{
if(aCoefficients[aIndex] != 0)
{
int aScalar = this.GField.Product(inverseOtherLeadingTerm, aCoefficients[aIndex]);
Polynomial term = other.MultiplyScalar(aScalar);
qCoefficients[aIndex] = aScalar;
int[] bCoefficient = term.Coefficients;
if(bCoefficient[0] != 0)
{
for(int bIndex = 0; bIndex < bLength; bIndex++)
{
aCoefficients[aIndex + bIndex] = this.GField.Subtraction(aCoefficients[aIndex + bIndex], bCoefficient[bIndex]);
}
}
}
}
return new PolyDivideStruct(new Polynomial(this.GField, qCoefficients),
new Polynomial(this.GField, aCoefficients));
}
}
