time frame handling in listmode reconstruction

[KrisThielemans]

• We do not have a set_time_interval yet for the list-mode objective function. It looks like this can be done in STIR by taking the objective function and setting its (public) frame_defs member. See also listmode reconstruction and time frame: missing set functions UCL/STIR#1417
• Our demo sets a time interval for the creation of the scatter etc here, but as listmode reconstruction will be using all events, there is going to be a mismatch, so this is a bug.

@evgueni-ovtchinnikov easy to add a set_time_interval method to the listmode objective function?

[evgueni-ovtchinnikov]

I understand it is not in STIR yet? Once you make it available in STIR, should not be difficult to access it from SIRF.

[KrisThielemans]

It doesn't need STIR modifications luckily.

Essentially a copy of ListmodeToSinograms::set_time_interval, i.e. adding set_time_interval to xSTIR_PoissonLLhLinModMeanListDataProjMatBin3DF (as [here](e.g.

SIRF/src/xSTIR/cSTIR/include/sirf/STIR/stir_x.h

Lines 141 to 148 in 2c66faf

	void set_time_interval(double start, double stop)
	{
	std::pair<double, double> interval(start, stop);
	std::vector < std::pair<double, double> > intervals;
	intervals.push_back(interval);
	frame_defs = stir::TimeFrameDefinitions(intervals);
	do_time_frame = true;
	}

)) and exposing it in exactly the same way

[evgueni-ovtchinnikov]

fixed by #1253