public Layer Solve(int needLayer)
{
if (!problem.IsAgreed)
{
return null;
}
var firstLayer = new Layer(Nx + 1) { Number = 0 };
Func<Layer, Layer> Next;
if (problem.a > 0)
{
Next = NextApositive;
}
else
{
Next = NextAnegative;
}
for (int i = 0; i <= Nx; i++)
{
firstLayer[i] = problem.U0(GetXValue(i));
}
for (int i = 1; i <= needLayer; ++i)
{
firstLayer = Next(firstLayer);
}
return firstLayer;
}
private Layer NextAnegative(Layer last)
{
var secondLayer = new Layer(Nx + 1) { Number = last.Number + 1 };
secondLayer[Nx] = problem.psi(GetTimeValue(secondLayer.Number));
for (int i = Nx - 1; i >= 0; i--)
{
secondLayer[i] = GetValueAnegative(last,secondLayer, i);
}
return secondLayer;
}
private double GetValueApositive(Layer last, Layer cur, int i)
{
double lam = problem.a*ht/hx;
return (problem.f(GetXValue(i), GetTimeValue(last.Number)) * ht + last[i] + lam * cur[i - 1]) / (1 + lam);
}
private Layer NextApositive(Layer last)
{
var secondLayer = new Layer(Nx + 1) { Number = last.Number + 1 };
secondLayer[0] = problem.psi(GetTimeValue(secondLayer.Number));
for (int i = 1; i <= Nx; i++)
{
secondLayer[i] = GetValueApositive(last,secondLayer, i);
}
return secondLayer;
}
private double GetValueApositive(Layer last, int i)
{
return last[i] - (problem.a * ht / hx * (last[i] - last[i - 1]))
+ ht * problem.f(GetXValue(i), GetTimeValue(last.Number));
}
