public override bool VisitSubtraction(TExpr left, TExpr right, TExpr original, Dummy data)
{
Polynomial <TVar, TExpr> polyLeft, polyRight;
if (!Build(left, out polyLeft) || !Build(right, out polyRight))
{
return(false);
}
long kLeft, kRight;
object subtraction;
if (polyLeft.IsIntConstant(out kLeft) && polyRight.IsIntConstant(out kRight) &&
EvaluateArithmeticWithOverflow.TryBinary(Decoder.TypeOf(original), ExpressionOperator.Sub, kLeft, kRight, out subtraction))
{
var longValue = subtraction.ConvertToLong();
if (longValue.HasValue)
{
return(true.With(new Polynomial <TVar, TExpr> (Monomial <TVar> .From(Rational.For(longValue.Value))), out poly));
}
}
return(TryToPolynomialHelperForSubtraction(polyLeft, polyRight, out poly));
}
public static Monomial <TVar> From(Rational coeff, IEnumerable <TVar> vars)
{
return(From(coeff, vars, seq => seq));
}
static bool TrySimplifyMonomes(Monomial <TVar>[] monomes, out Monomial <TVar>[] result)
{
if (monomes.Length <= 1)
{
return(true.With(monomes, out result));
}
var dict = new Dictionary <ListEqual <TVar>, Monomial <TVar> > ();
foreach (var monomial in monomes)
{
var key = new ListEqual <TVar> (monomial.Degree, monomial.Variables);
Monomial <TVar> monome;
if (dict.TryGetValue(key, out monome))
{
Rational coeff;
if (!Rational.TryAdd(monome.Coeff, monomial.Coeff, out coeff))
{
return(false.With(monomes, out result));
}
var sum = monome.With(coeff);
dict[key] = sum;
}
else
{
dict.Add(key, monomial);
}
}
var left = new List <Monomial <TVar> > (dict.Count);
var right = new List <Monomial <TVar> > (dict.Count);
Monomial <TVar>?resMonome = null;
foreach (var pair in dict)
{
var monome = pair.Value;
if (!monome.Coeff.IsZero)
{
if (monome.IsConstant)
{
resMonome = monome;
}
else if (monome.Coeff > 0L)
{
left.Add(monome);
}
else
{
right.Add(monome);
}
}
}
var list = new List <Monomial <TVar> > (dict.Count);
list.AddRange(left);
list.AddRange(right);
if (resMonome.HasValue)
{
list.Add(resMonome.Value);
}
if (list.Count == 0)
{
list.Add(Monomial <TVar> .From(Rational.Zero));
}
return(true.With(list.ToArray(), out result));
}
public static Monomial <TVar> From(Rational coeff)
{
return(new Monomial <TVar> (coeff));
}
public static Monomial <TVar> From(Rational coeff, Sequence <TVar> vars)
{
return(From(coeff, vars, seq => seq.AsEnumerable()));
}
public Monomial <TVar> With(Rational coeff)
{
return(new Monomial <TVar> (coeff, variables));
}
public override Interval RightOpen(Rational lowerBound)
{
return(Interval.For(lowerBound, Rational.PlusInfinity));
}
public override Interval LeftOpen(Rational upperBound)
{
return(Interval.For(Rational.MinusInfinity, upperBound));
}
public override Interval For(Rational lower, Rational upper)
{
return(Interval.For(lower, upper));
}
public override Interval For(Rational value)
{
return(Interval.For(value));
}
