Improve parameter checks for flowrate_filter

[schmoelder]

This is an initial draft to improve parameter checks.

In the given example, the FLOWRATE_FILTER accidentally did not have enough entries. Because its length was still > 0, CADET assumed it was a section depenent parameter. However, when compiled with g++, the CADET would exceed the bounds of the array and only (sometimes) crash much later. On Windows, it crashes immediately when exceeding the bounds of the array.

By calling getSectionDependentScalar(_flowRateFilter, secIdx) instead of indexing directly, it also crashes on Linux.

A more elegant approach would be to check the length of section dependent parameters before even starting the simulation. This way, the user knows directly that the configuration is invalid. @sleweke is this done somewhere in CADET for other section dependent parameters? I couldn't find anything.

Example

Partially fixes #28

[sleweke-bayer]

You propose to change CSTRModel::notifyDiscontinuousSectionTransition() to

void CSTRModel::notifyDiscontinuousSectionTransition(double t, unsigned int secIdx, const ConstSimulationState& simState, const AdJacobianParams& adJac)
{
	if (_flowRateFilter.size() > 1)
	{
		_curFlowRateFilter = getSectionDependentScalar(_flowRateFilter, secIdx);
	}
	else if (_flowRateFilter.size() == 1)
	{
		_curFlowRateFilter = _flowRateFilter[0];
	}
}

You can further simplify, because this is equivalent:

void CSTRModel::notifyDiscontinuousSectionTransition(double t, unsigned int secIdx, const ConstSimulationState& simState, const AdJacobianParams& adJac)
{
	_curFlowRateFilter = getSectionDependentScalar(_flowRateFilter, secIdx);
}

[sleweke-bayer]

is this done somewhere in CADET for other section dependent parameters? I couldn't find anything.

I don't know either. Would need to scan through the code as well.

[sleweke-bayer]

If this is deleted, section times will not be propagated into the models. But, this is required for the inlet profiles to work.