double RemoveLowResTOF::calcTofMin(const std::size_t workspaceIndex) {
const Kernel::V3D &sourcePos = m_instrument->getSource()->getPos();
const Kernel::V3D &samplePos = m_sample->getPos();
const Kernel::V3D &beamline = samplePos - sourcePos;
double beamline_norm = 2. * beamline.norm();
// Get a vector of detector IDs
std::vector<detid_t> detNumbers;
const std::set<detid_t> &detSet =
m_inputWS->getSpectrum(workspaceIndex)->getDetectorIDs();
detNumbers.assign(detSet.begin(), detSet.end());
double tmin = 0.;
if (isEmpty(m_wavelengthMin)) {
std::map<detid_t, double> offsets; // just an empty offsets map
double dspmap =
Instrument::calcConversion(m_L1, beamline, beamline_norm, samplePos,
m_instrument, detNumbers, offsets);
// this is related to the reference tof
double sqrtdmin =
sqrt(m_Tmin / m_DIFCref) + m_K * log10(dspmap * m_DIFCref);
if (sqrtdmin <= 0.)
return 0.;
tmin = sqrtdmin * sqrtdmin / dspmap;
if (tmin != tmin) {
g_log.warning() << "tmin is nan because dspmap = " << dspmap << ".\n";
}
} else {
double l2 = 0;
for (std::set<detid_t>::const_iterator it = detSet.begin();
it != detSet.end(); ++it) {
l2 += m_instrument->getDetector(*it)->getDistance(*m_sample);
}
l2 /= static_cast<double>(detSet.size());
Kernel::Unit_sptr wavelength = UnitFactory::Instance().create("Wavelength");
// unfortunately there isn't a good way to convert a single value
std::vector<double> X(1), temp(1);
X[0] = m_wavelengthMin;
wavelength->toTOF(X, temp, m_L1, l2, 0., 0, 0., 0.);
tmin = X[0];
}
g_log.debug() << "tmin[" << workspaceIndex << "] " << tmin << "\n";
return tmin;
}
double RemoveLowResTOF::calcTofMin(const std::size_t workspaceIndex,
const SpectrumInfo &spectrumInfo) {
const double l1 = spectrumInfo.l1();
// Get a vector of detector IDs
std::vector<detid_t> detNumbers;
const auto &detSet = m_inputWS->getSpectrum(workspaceIndex).getDetectorIDs();
detNumbers.assign(detSet.begin(), detSet.end());
double tmin = 0.;
if (isEmpty(m_wavelengthMin)) {
std::map<detid_t, double> offsets; // just an empty offsets map
Geometry::Instrument_const_sptr instrument = m_inputWS->getInstrument();
double dspmap = Conversion::tofToDSpacingFactor(
l1, spectrumInfo.l2(workspaceIndex),
spectrumInfo.twoTheta(workspaceIndex), detNumbers, offsets);
// this is related to the reference tof
double sqrtdmin =
sqrt(m_Tmin / m_DIFCref) + m_K * log10(dspmap * m_DIFCref);
if (sqrtdmin <= 0.)
return 0.;
tmin = sqrtdmin * sqrtdmin / dspmap;
if (tmin != tmin) {
g_log.warning() << "tmin is nan because dspmap = " << dspmap << ".\n";
}
} else {
const double l2 = spectrumInfo.l2(workspaceIndex);
Kernel::Unit_sptr wavelength = UnitFactory::Instance().create("Wavelength");
// unfortunately there isn't a good way to convert a single value
std::vector<double> X(1), temp(1);
X[0] = m_wavelengthMin;
wavelength->toTOF(X, temp, l1, l2, 0., 0, 0., 0.);
tmin = X[0];
}
g_log.debug() << "tmin[" << workspaceIndex << "] " << tmin << "\n";
return tmin;
}