/**
* Compute time derivative of state at current time.
* This is used by the time-integration "mod.compute(t)" as the core of the model.
* @return vector dt
*/
protected override IVector Dx(IVector xt, double t)
{
IVector result = new VectorJ2N(2);
// The oscillator model
//
// simple linear oscilator (e.g. mass-spring system with friction)
//% d(x)/d(t) = u
// d(u)/d(t) = - omega^2 * x - (2/t_damp) u
//
double[] x = xt.Values;
double omega = Math.Max(0.0, parameterValues[omegaId]);
double tDamp = Math.Max(0.0, parameterValues[tDampId]);
result.SetValue(0, x[1]);
result.SetValue(1, -(omega * omega) * x[0] - (2.0 / tDamp * x[1]));
return(result);
}
public IVector GetObservedValues(IObservationDescriptions descr)
{
IVector result = new VectorJ2N(descr.ObservationCount);
// TODO: handle TimeSeriesObservationDescriptions
IVector obsTimes = descr.GetValueProperties("time");
IVector obsIndex = descr.GetValueProperties("index") ?? descr.GetValueProperties("xPosition");
IVector transformIndex;
try
{
transformIndex = descr.GetValueProperties("transform");
}
catch (Exception)
{
transformIndex = null;
}
Time tHor = new Time(parameterValues[StartTimeId],
parameterValues[StopTimeId])
;
tHor.StepMJD = parameterValues[TimeStepId];
if (storeObs)
{
//work from stored states
for (int i = 0; i < descr.ObservationCount; i++)
{
// at which timestep is this obs
long iObs = Utils.GetTimeStep(tHor, (new Time(obsTimes.GetValue(i))));
// find corresponding storage location
int thisTIndex = iStore.IndexOf((int)iObs); //time index in storage
if (thisTIndex < 0)
{
throw (new Exception("model.getValues: time out of range for observation nr. " + i));
}
int thisXIndex = (int)obsIndex.GetValue(i);
if ((thisXIndex < 0) | (thisXIndex >= state.Size))
{
throw (new Exception("model.getValues: index out of range for "
+ " observation nr. " + i
+ " index= " + thisXIndex));
}
//Console.Out.WriteLine("i="+i+" it="+thisTIndex+" ind= "+thisXIndex);
double thisValue = xStore[thisTIndex].GetValue(thisXIndex);
// transform values if needed
if (transformIndex != null)
{
if (transformIndex.GetValue(i) == 2)
{
// magic number for quadratic observations
thisValue = thisValue * thisValue;
}
}
result.SetValue(i, thisValue);
}
}
else
{
// only current state is available
for (int i = 0; i < descr.ObservationCount; i++)
{
int thisXIndex = (int)obsIndex.GetValue(i);
//TODO if(){ //check time
double thisValue = state.GetValue(thisXIndex);
// transform values if needed
if (transformIndex != null)
{
if (transformIndex.GetValue(i) == 2)
{
// magic number for quadratic observations
thisValue = thisValue * thisValue;
}
}
result.SetValue(i, thisValue);
}
}
return(result);
}