public override INumber Execute(RuntimeData runtime, params INumber[] parameters)
{
var param0 = parameters[0];
if (param0 is Variable || param0 is Member)
{
string t = "";
if (param0 is Variable)
{
t = (param0 as Variable).Name;
}
if (param0 is Member)
{
t = (param0 as Member).Text;
}
if (t == "e")
{
param0 = new NaturalLogarithm();
}
}
else
{
param0 = param0.Eval(runtime);
}
return(new FuncedINumber(this, new INumber[] { param0, parameters[1].Eval(runtime) }));
}
public INumber ExecuteDiff(RuntimeData runtime, string t, INumber[] parameters)
{
// log(xy) => log(x) + log(y)
if (parameters[1] is MultipleFormula)
{
AdditionFormula af = new Expression.AdditionFormula();
foreach (var item in (parameters[1] as MultipleFormula).Items)
{
af.AddItem(runtime, this.ExecuteDiff(runtime, t, new INumber[] { parameters[0], item }));
}
return(af);
}
if (parameters[1] is Fraction)
{
AdditionFormula af = new Expression.AdditionFormula();
Fraction f = parameters[1] as Fraction;
af.AddItem(runtime, this.ExecuteDiff(runtime, t, new INumber[] { parameters[0], f.Numerator }));
af.AddItem(runtime, this.ExecuteDiff(runtime, t, new INumber[] { parameters[0], f.Denominator }).Multiple(runtime, Number.New(-1)));
return(af);
}
// 普通のlogの微分
if (parameters[0] is NaturalLogarithm)
{
NaturalLogarithm e = parameters[0] as NaturalLogarithm;
if (e.Pow.Equals(runtime, Number.New(1)))
{
var prm = parameters[1].ExecuteDiff(runtime, t);
if (prm.Equals(runtime, Number.New(0)) ||
prm.Equals(runtime, Number.New(1)))
{
return(new Fraction(
parameters[1], Number.New(1)));
}
else
{
MultipleFormula mf = new Expression.MultipleFormula();
mf.AddItem(runtime, prm);
mf.AddItem(runtime, new Fraction(
parameters[1], Number.New(1)));
return(mf);
}
}
}
else if (!FuncCalc.Runtime.Func.Differential.IsConstValue(runtime, parameters[0]))
{
throw new RuntimeException("底に定数以外が含まれたlogの微分を行うことはできません。");
}
INumber param1Diff = parameters[1].ExecuteDiff(runtime, t);
if (param1Diff.Equals(runtime, Number.New(0)))
{
param1Diff = Number.New(1);
}
MultipleFormula den = new MultipleFormula();
den.AddItem(runtime, parameters[1]);
den.AddItem(runtime, new FuncedINumber(this, new INumber[] { new NaturalLogarithm(), parameters[0] }));
Fraction res = new Fraction(den, param1Diff);
return(res);
}
