public void Compute(ITime targetTime)
{
HandleExchangeItemsBeforeCompute();
double tStep = parameterValues[TimeStepId];
int nsteps = (int)Math.Round((targetTime.MJD - t) / tStep);
IVector x = state;
IVector xn;
for (int i = 0; i < nsteps; i++)
{
// --> Runge-Kutta
// System.out.print("step :"+i+" ");
// dx0 = dx(x,t);
IVector dxdt0 = Dx(x, t);
// dx1 = dx(x+0.5*dx0,t+0.5*dt);
xn = x.Clone();
xn.Axpy(0.5 * tStep, dxdt0);
IVector dxdt1 = Dx(xn, t + 0.5 * tStep);
// dx2 = dx(t+0.5*dt,x+0.5*dx1);
xn = x.Clone();
xn.Axpy(0.5 * tStep, dxdt1);
IVector dxdt2 = Dx(xn, t + 0.5 * tStep);
// dx3 = dx(t+1.0*dt,x+1.0*dx2);
xn = x.Clone();
xn.Axpy(1.0 * tStep, dxdt2);
IVector dxdt3 = Dx(xn, t + 0.5 * tStep);
// x = x + 1/6*dt*(dx0+2*dx1+2*dx2+dx3);
x.Axpy(1.0 / 6.0 * tStep, dxdt0);
x.Axpy(2.0 / 6.0 * tStep, dxdt1);
x.Axpy(2.0 / 6.0 * tStep, dxdt2);
x.Axpy(1.0 / 6.0 * tStep, dxdt3);
t += tStep;
timeStep++;
// Console.Out.WriteLine(">>>>>>> t="+t+" x="+x);
if (storeObs)
{
// store all states if this is requested
tStore.Add(t);
xStore.Add(x.Clone());
iStore.Add(timeStep);
}
if (outputLevel != OutputLevel.Suppress)
{
ResultsJ2N.PutValue("model_time", t, MessageType.Step);
ResultsJ2N.PutValue("x", x, MessageType.Step);
}
}
state.Values = x.Values;
t += tStep;
UpdateExchangeItemsAfterCompute();
}
