internal static Algebraic remove_constant(Algebraic expr, Variable x)
{
if (!expr.Depends(x))
{
return(Symbolic.ZERO);
}
if (expr is Polynomial)
{
(( Polynomial )expr)[0] = remove_constant((( Polynomial )expr)[0], x);
return(expr);
}
if (expr is Rational)
{
var den = (( Rational )expr).den;
var nom = (( Rational )expr).nom;
if (!den.Depends(x))
{
return(remove_constant(nom, x) / den);
}
if (nom is Polynomial)
{
var a = new[] { nom, den };
Poly.polydiv(a, den._v);
if (!a[0].Depends(x))
{
return(a[1] / den);
}
}
}
return(expr);
}
public virtual Algebraic ratsubst(Algebraic expr)
{
if (gcd.Equals(Symbolic.ZERO))
{
return(expr);
}
if (!expr.Depends(@var))
{
return(expr);
}
if (expr is Rational)
{
return(ratsubst((( Rational )expr).nom) / ratsubst((( Rational )expr).den));
}
if (expr is Polynomial && ((Polynomial)expr)._v is FunctionVariable &&
((FunctionVariable)((Polynomial)expr)._v).Name.Equals("exp") &&
((FunctionVariable)((Polynomial)expr)._v).Var is Polynomial &&
((Polynomial)((FunctionVariable)((Polynomial)expr)._v).Var)._v.Equals(@var) &&
((Polynomial)((FunctionVariable)((Polynomial)expr)._v).Var).Degree() == 1 &&
((Polynomial)((FunctionVariable)((Polynomial)expr)._v).Var)[0].Equals(Symbolic.ZERO))
{
Polynomial pexpr = (Polynomial)expr;
int degree = pexpr.Degree();
Algebraic[] a = new Algebraic[degree + 1];
for (int i = 0; i <= degree; i++)
{
Algebraic cf = pexpr[i];
if (cf.Depends(@var))
{
throw new JasymcaException("Rationalize failed: 2");
}
a[i] = cf;
}
return(new Polynomial(t, a));
}
throw new JasymcaException("Could not rationalize " + expr);
}
public override bool Depends(Variable v)
{
return(nom.Depends(v) || den.Depends(v));
}
//JAVA TO C# CONVERTER WARNING: Method 'throws' clauses are not available in .NET:
//ORIGINAL LINE: Vektor solve(Vector expr, Vector x, int n) throws JasymcaException
internal virtual Vector solve(ArrayList expr, ArrayList x, int n)
{
Algebraic equ = null;
Variable v = null;
int i, k, iv = 0, ke = 0;
for (i = 0; i < n && equ == null; i++)
{
v = (Variable)x[i];
double norm = -1.0;
for (k = 0; k < n; k++)
{
Algebraic exp = (Algebraic)expr[k];
if (exp is Rational)
{
exp = ((Rational)exp).nom;
}
Algebraic slope = exp.Derive(v);
if (!slope.Equals(Symbolic.ZERO) && slope is Symbolic)
{
double nm = slope.Norm() / exp.Norm();
if (nm > norm)
{
norm = nm;
equ = exp;
ke = k;
iv = i;
}
}
}
}
if (equ == null)
{
for (i = 0; i < n && equ == null; i++)
{
v = (Variable)x[i];
for (k = 0; k < n; k++)
{
Algebraic exp = (Algebraic)expr[k];
if (exp is Rational)
{
exp = ((Rational)exp).nom;
}
if (exp.Depends(v))
{
equ = exp;
ke = k;
iv = i;
break;
}
}
}
}
if (equ == null)
{
throw new JasymcaException("Expressions do not depend of Variables.");
}
Vector sol = LambdaSOLVE.solve(equ, v);
expr.RemoveAt(ke);
expr.Insert(n - 1, equ);
x.RemoveAt(iv);
x.Insert(n - 1, v);
return(sol);
}
