/** Gets the distances between the source and detectors whose IDs you pass to it
* @param WS :: the input workspace
* @param mon0Spec :: Spectrum number of the output from the first monitor
* @param mon1Spec :: Spectrum number of the output from the second monitor
* @param monitor0Dist :: the calculated distance to the detector whose ID was passed to this function first
* @param monitor1Dist :: calculated distance to the detector whose ID was passed to this function second
* @throw NotFoundError if no detector is found for the detector ID given
* @throw runtime_error if there is a problem with the SpectraDetectorMap
*/
void GetEi::getGeometry(API::MatrixWorkspace_const_sptr WS, specid_t mon0Spec, specid_t mon1Spec, double &monitor0Dist, double &monitor1Dist) const
{
const IObjComponent_const_sptr source = WS->getInstrument()->getSource();
// retrieve a pointer to the first detector and get its distance
size_t monWI = 0;
try
{
monWI = WS->getIndexFromSpectrumNumber(mon0Spec);
}
catch (std::runtime_error &)
{
g_log.error() << "Could not find the workspace index for the monitor at spectrum " << mon0Spec << "\n";
g_log.error() << "Error retrieving data for the first monitor" << std::endl;
throw std::bad_cast();
}
const std::set<detid_t> & dets = WS->getSpectrum(monWI)->getDetectorIDs();
if ( dets.size() != 1 )
{
g_log.error() << "The detector for spectrum number " << mon0Spec << " was either not found or is a group, grouped monitors are not supported by this algorithm\n";
g_log.error() << "Error retrieving data for the first monitor" << std::endl;
throw std::bad_cast();
}
IDetector_const_sptr det = WS->getInstrument()->getDetector(*dets.begin());
monitor0Dist = det->getDistance(*(source.get()));
// repeat for the second detector
try
{
monWI = WS->getIndexFromSpectrumNumber(mon0Spec);
}
catch (std::runtime_error &)
{
g_log.error() << "Could not find the workspace index for the monitor at spectrum " << mon0Spec << "\n";
g_log.error() << "Error retrieving data for the second monitor\n";
throw std::bad_cast();
}
const std::set<detid_t> & dets2 = WS->getSpectrum(monWI)->getDetectorIDs();
if ( dets2.size() != 1 )
{
g_log.error() << "The detector for spectrum number " << mon1Spec << " was either not found or is a group, grouped monitors are not supported by this algorithm\n";
g_log.error() << "Error retrieving data for the second monitor\n";
throw std::bad_cast();
}
det = WS->getInstrument()->getDetector(*dets2.begin());
monitor1Dist = det->getDistance(*(source.get()));
}
