void ConvertToDiffractionMDWorkspace::convertEventList(int workspaceIndex,
EventList &el) {
size_t numEvents = el.getNumberEvents();
DataObjects::MDBoxBase<DataObjects::MDLeanEvent<3>, 3> *box = ws->getBox();
// Get the position of the detector there.
const std::set<detid_t> &detectors = el.getDetectorIDs();
if (!detectors.empty()) {
// Get the detector (might be a detectorGroup for multiple detectors)
// or might return an exception if the detector is not in the instrument
// definition
IDetector_const_sptr det;
try {
det = m_inWS->getDetector(workspaceIndex);
} catch (Exception::NotFoundError &) {
this->failedDetectorLookupCount++;
return;
}
// Vector between the sample and the detector
V3D detPos = det->getPos() - samplePos;
// Neutron's total travelled distance
double distance = detPos.norm() + l1;
// Detector direction normalized to 1
V3D detDir = detPos / detPos.norm();
// The direction of momentum transfer in the inelastic convention ki-kf
// = input beam direction (normalized to 1) - output beam direction
// (normalized to 1)
V3D Q_dir_lab_frame = beamDir - detDir;
double qSign = -1.0;
std::string convention =
ConfigService::Instance().getString("Q.convention");
if (convention == "Crystallography")
qSign = 1.0;
Q_dir_lab_frame *= qSign;
// Multiply by the rotation matrix to convert to Q in the sample frame (take
// out goniometer rotation)
// (or to HKL, if that's what the matrix is)
V3D Q_dir = mat * Q_dir_lab_frame;
// For speed we extract the components.
coord_t Q_dir_x = coord_t(Q_dir.X());
coord_t Q_dir_y = coord_t(Q_dir.Y());
coord_t Q_dir_z = coord_t(Q_dir.Z());
// For lorentz correction, calculate sin(theta))^2
double sin_theta_squared = 0;
if (LorentzCorrection) {
// Scattering angle = 2 theta = angle between neutron beam direction and
// the detector (scattering) direction
// The formula for Lorentz Correction is sin(theta), i.e. sin(half the
// scattering angle)
double theta = detDir.angle(beamDir) / 2.0;
sin_theta_squared = sin(theta);
sin_theta_squared = sin_theta_squared * sin_theta_squared; // square it
}
/** Constant that you divide by tof (in usec) to get wavenumber in ang^-1 :
* Wavenumber (in ang^-1) = (PhysicalConstants::NeutronMass * distance) /
* ((tof (in usec) * 1e-6) * PhysicalConstants::h_bar) * 1e-10; */
const double wavenumber_in_angstrom_times_tof_in_microsec =
(PhysicalConstants::NeutronMass * distance * 1e-10) /
(1e-6 * PhysicalConstants::h_bar);
// PARALLEL_CRITICAL( convert_tester_output ) { std::cout << "Spectrum " <<
// el.getSpectrumNo() << " beamDir = " << beamDir << " detDir = " << detDir
// << " Q_dir = " << Q_dir << " conversion factor " <<
// wavenumber_in_angstrom_times_tof_in_microsec << std::endl; }
// g_log.information() << wi << " : " << el.getNumberEvents() << " events.
// Pos is " << detPos << std::endl;
// g_log.information() << Q_dir.norm() << " Qdir norm" << std::endl;
// This little dance makes the getting vector of events more general (since
// you can't overload by return type).
typename std::vector<T> *events_ptr;
getEventsFrom(el, events_ptr);
typename std::vector<T> &events = *events_ptr;
// Iterators to start/end
auto it = events.begin();
auto it_end = events.end();
for (; it != it_end; it++) {
// Get the wavenumber in ang^-1 using the previously calculated constant.
coord_t wavenumber =
coord_t(wavenumber_in_angstrom_times_tof_in_microsec / it->tof());
// Q vector = K_final - K_initial = wavenumber * (output_direction -
// input_direction)
coord_t center[3] = {Q_dir_x * wavenumber, Q_dir_y * wavenumber,
Q_dir_z * wavenumber};
// Check that the event is within bounds
if (center[0] < m_extentsMin[0] || center[0] >= m_extentsMax[0])
continue;
if (center[1] < m_extentsMin[1] || center[1] >= m_extentsMax[1])
continue;
if (center[2] < m_extentsMin[2] || center[2] >= m_extentsMax[2])
continue;
if (LorentzCorrection) {
// double lambda = 1.0/wavenumber;
// (sin(theta))^2 / wavelength^4
float correct = float(sin_theta_squared * wavenumber * wavenumber *
wavenumber * wavenumber);
// Push the MDLeanEvent but correct the weight.
box->addEvent(MDE(float(it->weight() * correct),
float(it->errorSquared() * correct * correct),
center));
} else {
// Push the MDLeanEvent with the same weight
box->addEvent(
MDE(float(it->weight()), float(it->errorSquared()), center));
}
}
// Clear out the EventList to save memory
if (ClearInputWorkspace) {
// Track how much memory you cleared
size_t memoryCleared = el.getMemorySize();
// Clear it now
el.clear();
// For Linux with tcmalloc, make sure memory goes back, if you've cleared
// 200 Megs
MemoryManager::Instance().releaseFreeMemoryIfAccumulated(
memoryCleared, static_cast<size_t>(2e8));
}
}
prog->reportIncrement(numEvents, "Adding Events");
}
