public static Aad Tan(Aad x)
{
var res = new Aad(() => Math.Tan(x.Value));
if (x.IsVariable)
{
AadCalculationStack.Instance.Add(x.Index, res.Index, () => 1.0 + Math.Tan(x.Value) * Math.Tan(x.Value));
}
return(res);
}
public static Aad operator *(Aad left, Aad right)
{
var res = new Aad(() => left.Value * right.Value);
if (left.IsVariable)
{
AadCalculationStack.Instance.Add(left.Index, res.Index, () => right.Value);
}
if (right.IsVariable)
{
AadCalculationStack.Instance.Add(right.Index, res.Index, () => left.Value);
}
return(res);
}
public static Aad Max(Aad lhs, Aad rhs)
{
var res = new Aad(() => Math.Max(lhs.Value, rhs.Value));
if (lhs.IsVariable)
{
AadCalculationStack.Instance.Add(lhs.Index, res.Index, () => lhs.Value > rhs.Value ? 1.0 : 0.0);
}
if (rhs.IsVariable)
{
AadCalculationStack.Instance.Add(rhs.Index, res.Index, () => rhs.Value > lhs.Value ? 1.0 : 0.0);
}
return(res);
}
public double Derivative(Aad variable)
{
if (!variable.IsVariable)
{
return(0.0);
}
var stack = AadCalculationStack.Instance;
var data = stack.Data.ToArray();
var vals = new double[Index + 1];
vals[Index] = 1.0;
for (var i = 1; i <= data.Length; ++i)
{
var derivData = data[data.Length - i];
if (derivData.DerivTarget <= Index)
{
vals[derivData.DerivBy] += derivData.Value * vals[derivData.DerivTarget];
}
}
return(vals[variable.Index]);
}