/// <summary> /// Sets the coefficient at <c>Index</c> to <c>Element</c> /// </summary> /// /// <param name="Index">The index</param> /// <param name="E">The GF2nElement to store as coefficient <c>Index</c></param> public void Set(int Index, GF2nElement E) { if (!(E is GF2nPolynomialElement) && !(E is GF2nONBElement)) { throw new ArgumentException("GF2nPolynomial: PolynomialGF2n.Set f must be an instance of either GF2nPolynomialElement or GF2nONBElement!"); } _coeff[Index] = (GF2nElement)E.Clone(); }
/// <summary> /// Creates a new PolynomialGF2n of size <c>Degree</c> and elem as coefficients /// </summary> /// /// <param name="Degree">The maximum degree + 1</param> /// <param name="Element">A GF2nElement</param> public GF2nPolynomial(int Degree, GF2nElement Element) { _size = Degree; _coeff = new GF2nElement[_size]; for (int i = 0; i < _size; i++) { _coeff[i] = (GF2nElement)Element.Clone(); } }
/// <summary> /// Converts the given element in representation according to this field to a new element in /// representation according to B1 using the change-of-basis matrix calculated by computeCOBMatrix. /// </summary> /// /// <param name="Elem">The GF2nElement to convert</param> /// <param name="Basis">The basis to convert <c>Elem</c> to</param> /// /// <returns>Returns <c>Elem</c> converted to a new element representation according to <c>basis</c></returns> public GF2nElement Convert(GF2nElement Elem, GF2nField Basis) { if (Basis == this) { return((GF2nElement)Elem.Clone()); } if (FieldPoly.Equals(Basis.FieldPoly)) { return((GF2nElement)Elem.Clone()); } if (DegreeN != Basis.DegreeN) { throw new Exception("GF2nField.Convert: B1 has a different degree and thus cannot be coverted to!"); } int i; GF2Polynomial[] COBMatrix; i = Fields.IndexOf(Basis); if (i == -1) { ComputeCOBMatrix(Basis); i = Fields.IndexOf(Basis); } COBMatrix = (GF2Polynomial[])Matrices[i]; GF2nElement elemCopy = (GF2nElement)Elem.Clone(); if (elemCopy is GF2nONBElement) { ((GF2nONBElement)elemCopy).ReverseOrder(); } GF2Polynomial bs = new GF2Polynomial(DegreeN, elemCopy.ToFlexiBigInt()); bs.ExpandN(DegreeN); GF2Polynomial result = new GF2Polynomial(DegreeN); for (i = 0; i < DegreeN; i++) { if (bs.VectorMult(COBMatrix[i])) { result.SetBit(DegreeN - 1 - i); } } if (Basis is GF2nPolynomialField) { return(new GF2nPolynomialElement((GF2nPolynomialField)Basis, result)); } else if (Basis is GF2nONBField) { GF2nONBElement res = new GF2nONBElement((GF2nONBField)Basis, result.ToFlexiBigInt()); res.ReverseOrder(); return(res); } else { throw new Exception("GF2nField.convert: B1 must be an instance of GF2nPolynomialField or GF2nONBField!"); } }