/// <summary>
/// Method for multiplying current bivariate polynomial by bivariate polynomial <paramref name="b"/>
/// </summary>
/// <param name="b">Factor</param>
public BiVariablePolynomial Multiply(BiVariablePolynomial b)
{
var coeficientsArray = _coefficients.ToArray();
_coefficients.Clear();
if (b.IsZero)
{
return(this);
}
foreach (var coefficient in coeficientsArray)
{
foreach (var otherCoefficient in b._coefficients)
{
FieldElement coeficientValue;
var monomial = new Tuple <int, int>(coefficient.Key.Item1 + otherCoefficient.Key.Item1,
coefficient.Key.Item2 + otherCoefficient.Key.Item2);
if (_coefficients.TryGetValue(monomial, out coeficientValue) == false)
{
coeficientValue = Field.Zero();
_coefficients[monomial] = coeficientValue;
}
coeficientValue.Add(coefficient.Value * otherCoefficient.Value);
}
}
return(RemoveZeroCoefficients());
}
/// <summary>
/// Method for subtracting bivariate polynomial <paramref name="other"/> multiplied by <paramref name="b"/> from current bivariate polynomial
/// </summary>
/// <param name="b">Subtrahend multiplier</param>
/// <param name="other">Subtrahend</param>
public BiVariablePolynomial Subtract(FieldElement b, BiVariablePolynomial other)
{
if (Field.Equals(b.Field) == false)
{
throw new ArgumentException(nameof(b));
}
if (Field.Equals(other.Field) == false)
{
throw new ArgumentException(nameof(other));
}
if (b.Representation == 0)
{
return(this);
}
foreach (var otherCoefficient in other._coefficients)
{
FieldElement coeficientValue;
if (_coefficients.TryGetValue(otherCoefficient.Key, out coeficientValue) == false)
{
coeficientValue = Field.Zero();
_coefficients[otherCoefficient.Key] = coeficientValue;
}
coeficientValue.Subtract(b * otherCoefficient.Value);
if (coeficientValue.Representation == 0)
{
_coefficients.Remove(otherCoefficient.Key);
}
}
return(this);
}
/// <summary>
/// Constructor for creating copy of the bivariate polynomial <paramref name="polynomial"/>
/// </summary>
/// <param name="polynomial">Copied bivariate polynomial</param>
public BiVariablePolynomial(BiVariablePolynomial polynomial)
{
if (polynomial == null)
{
throw new ArgumentNullException(nameof(polynomial));
}
Field = polynomial.Field;
_coefficients = polynomial._coefficients.ToDictionary(x => x.Key, x => new FieldElement(x.Value));
}
/// <summary>
/// Method for multiplying field elemnt <paramref name="a"/> by bivariate polynomial <paramref name="b"/>
/// </summary>
/// <param name="a">First factor</param>
/// <param name="b">Second factor</param>
public static BiVariablePolynomial Multiply(FieldElement a, BiVariablePolynomial b)
{
var c = new BiVariablePolynomial(b);
return(c.Multiply(a));
}
/// <summary>
/// Method for multiplying bivariate polynomial <paramref name="a"/> by field elemnt <paramref name="b"/>
/// </summary>
/// <param name="a">First factor</param>
/// <param name="b">Second factor</param>
public static BiVariablePolynomial Multiply(BiVariablePolynomial a, FieldElement b)
{
var c = new BiVariablePolynomial(a);
return(c.Multiply(b));
}
/// <summary>
/// Method for subtracting bivariate polynomial <paramref name="b"/> from <paramref name="a"/>
/// </summary>
/// <param name="a">Minuend</param>
/// <param name="b">Subtrahend</param>
public static BiVariablePolynomial Subtract(BiVariablePolynomial a, BiVariablePolynomial b)
{
var c = new BiVariablePolynomial(a);
return(c.Subtract(b));
}
/// <summary>
/// Method for adding bivariate polynomial <paramref name="b"/> to <paramref name="a"/>
/// </summary>
/// <param name="a">First term</param>
/// <param name="b">Second term</param>
public static BiVariablePolynomial Add(BiVariablePolynomial a, BiVariablePolynomial b)
{
var c = new BiVariablePolynomial(a);
return(c.Add(b));
}
/// <summary>
/// Method for checking the equality of the current bivariate polynomial to the <paramref name="other"/>
/// </summary>
/// <param name="other">Another bivariate polynomial</param>
/// <returns>Checking result</returns>
private bool Equals(BiVariablePolynomial other)
{
return(_coefficients.OrderBy(x => x.Key).SequenceEqual(other._coefficients.OrderBy(x => x.Key)) &&
Field.Equals(other.Field));
}
/// <summary>
/// Method for subtracting bivariate polynomial <paramref name="other"/> from current bivariate polynomial
/// </summary>
/// <param name="other">Subtrahend</param>
public BiVariablePolynomial Subtract(BiVariablePolynomial other)
{
return(Subtract(Field.One(), other));
}
/// <summary>
/// Method for adding bivariate polynomial <paramref name="other"/> to current bivariate polynomial
/// </summary>
/// <param name="other">Term</param>
public BiVariablePolynomial Add(BiVariablePolynomial other)
{
return(Add(Field.One(), other));
}