/***********************************************************************//**
* @brief Test CTA Npred computation
*
* Tests the Npred computation for the diffuse source model. This is done
* by loading the model from the XML file and by calling the
* GCTAObservation::npred method which in turn calls the
* GCTAResponse::npred_diffuse method. The test takes a few seconds.
***************************************************************************/
void TestGCTAResponse::test_response_npred_diffuse(void)
{
// Set reference value
double ref = 11212.26274;
// Set parameters
double src_ra = 201.3651;
double src_dec = -43.0191;
double roi_rad = 4.0;
// Setup ROI centred on Cen A with a radius of 4 deg
GCTARoi roi;
GCTAInstDir instDir;
instDir.radec_deg(src_ra, src_dec);
roi.centre(instDir);
roi.radius(roi_rad);
// Setup pointing on Cen A
GSkyDir skyDir;
skyDir.radec_deg(src_ra, src_dec);
GCTAPointing pnt;
pnt.dir(skyDir);
// Setup dummy event list
GGti gti;
GEbounds ebounds;
GTime tstart(0.0);
GTime tstop(1800.0);
GEnergy emin;
GEnergy emax;
emin.TeV(0.1);
emax.TeV(100.0);
gti.append(tstart, tstop);
ebounds.append(emin, emax);
GCTAEventList events;
events.roi(roi);
events.gti(gti);
events.ebounds(ebounds);
// Setup dummy CTA observation
GCTAObservation obs;
obs.ontime(1800.0);
obs.livetime(1600.0);
obs.deadc(1600.0/1800.0);
obs.response(cta_irf, cta_caldb);
obs.events(&events);
obs.pointing(pnt);
// Load models for Npred computation
GModels models(cta_rsp_xml);
// Perform Npred computation
double npred = obs.npred(models, NULL);
// Test Npred
test_value(npred, ref, 1.0e-5, "Diffuse Npred computation");
// Return
return;
}
/***********************************************************************//**
* @brief Compute position angle between instrument directions in radians
*
* @param[in] dir Instrument direction.
***************************************************************************/
double GCTAInstDir::posang(const GCTAInstDir& dir) const
{
// Assign sky direction from instrument direction
GSkyDir sky;
double ra = dir.ra();
double dec = dir.dec();
sky.radec(ra,dec);
// Compute position angle
double pa = m_dir.posang(sky);
// Return position angle
return pa;
}
/***********************************************************************//**
* @brief Compute angular distance between instrument directions in radians
*
* @param[in] dir Instrument direction.
***************************************************************************/
double GCTAInstDir::dist(const GCTAInstDir& dir) const
{
// Assign sky direction from instrument direction
GSkyDir sky;
double ra = dir.ra();
double dec = dir.dec();
sky.radec(ra,dec);
// Compute distance
double dist = m_dir.dist(sky);
// Return distance
return dist;
}
/***********************************************************************//**
* @brief Extract ROI from data sub-space keywords
*
* @param[in] hdu FITS HDU
*
* @exception GException::invalid_value
* Invalid ROI data sub-space encountered
*
* Reads the ROI data sub-space keywords by searching for a DSTYPx keyword
* named "POS(RA,DEC)". The data sub-space information is expected to be in
* the format "CIRCLE(267.0208,-24.78,4.5)", where the 3 arguments are Right
* Ascension, Declination and radius in units of degrees. No detailed syntax
* checking is performed.
*
* If no ROI information has been found, an GCTARoi object with initial
* values will be returned.
***************************************************************************/
GCTARoi gammalib::read_ds_roi(const GFitsHDU& hdu)
{
// Initialise ROI
GCTARoi roi;
// Get number of data sub-space keywords (default to 0 if keyword is
// not found)
int ndskeys = (hdu.has_card("NDSKEYS")) ? hdu.integer("NDSKEYS") : 0;
// Loop over all data selection keys
for (int i = 1; i <= ndskeys; ++i) {
// Set data sub-space key strings
std::string type_key = "DSTYP"+gammalib::str(i);
//std::string unit_key = "DSUNI"+gammalib::str(i);
std::string value_key = "DSVAL"+gammalib::str(i);
// Continue only if type_key is found and if this key is POS(RA,DEC)
if (hdu.has_card(type_key) && hdu.string(type_key) == "POS(RA,DEC)") {
// ...
//std::string unit = gammalib::toupper(hdu.string(unit_key));
std::string value = hdu.string(value_key);
std::string value_proc = gammalib::strip_chars(value, "CIRCLE(");
value_proc = gammalib::strip_chars(value_proc, ")");
std::vector<std::string> args = gammalib::split(value_proc, ",");
if (args.size() == 3) {
double ra = gammalib::todouble(args[0]);
double dec = gammalib::todouble(args[1]);
double rad = gammalib::todouble(args[2]);
GCTAInstDir dir;
dir.dir().radec_deg(ra, dec);
roi.centre(dir);
roi.radius(rad);
}
else {
std::string msg = "Invalid acceptance cone value \""+value+
"\" encountered in data sub-space "
"key \""+value_key+"\".";
throw GException::invalid_value(G_READ_DS_ROI, msg);
}
} // endif: POS(RA,DEC) type found
} // endfor: looped over data sub-space keys
// Return roi
return roi;
}
/***********************************************************************//**
* @brief Returns MC instrument direction
*
* @param[in] energy Photon energy.
* @param[in] time Photon arrival time.
* @param[in,out] ran Random number generator.
* @return CTA instrument direction.
***************************************************************************/
GCTAInstDir GCTABackgroundPerfTable::mc(const GEnergy& energy,
const GTime& time,
GRan& ran) const
{
// Simulate theta angle
#if defined(G_DEBUG_MC)
int n_samples = 0;
#endif
double sigma_max = 4.0 * std::sqrt(sigma());
double u_max = std::sin(sigma_max * gammalib::deg2rad);
double value = 0.0;
double u = 1.0;
double theta = 0.0;
do {
theta = ran.uniform() * sigma_max;
double arg = theta * theta / sigma();
double arg2 = arg * arg;
value = std::sin(theta * gammalib::deg2rad) * exp(-0.5 * arg2);
u = ran.uniform() * u_max;
#if defined(G_DEBUG_MC)
n_samples++;
#endif
} while (u > value);
theta *= gammalib::deg2rad;
#if defined(G_DEBUG_MC)
std::cout << "#=" << n_samples << " ";
#endif
// Simulate azimuth angle
double phi = gammalib::twopi * ran.uniform();
// Compute detx and dety
double detx(0.0);
double dety(0.0);
if (theta > 0.0 ) {
detx = theta * std::cos(phi);
dety = theta * std::sin(phi);
}
// Set instrument direction (in radians)
GCTAInstDir dir;
dir.detx(detx);
dir.dety(dety);
// Return instrument direction
return dir;
}
/***********************************************************************//**
* @brief Test CTA npsf computation
***************************************************************************/
void TestGCTAResponse::test_response_npsf(void)
{
// Setup CTA response
GCTAResponse rsp;
rsp.caldb(cta_caldb);
rsp.load(cta_irf);
// Setup npsf computation
GSkyDir srcDir;
GEnergy srcEng;
GTime srcTime;
GCTAPointing pnt;
GCTARoi roi;
GCTAInstDir instDir;
instDir.radec_deg(0.0, 0.0);
roi.centre(instDir);
roi.radius(2.0);
srcEng.TeV(0.1);
// Test PSF centred on ROI
srcDir.radec_deg(0.0, 0.0);
double npsf = rsp.npsf(srcDir, srcEng.log10TeV(), srcTime, pnt, roi);
test_value(npsf, 1.0, 1.0e-3, "PSF(0,0) integration");
// Test PSF offset but inside ROI
srcDir.radec_deg(1.0, 1.0);
npsf = rsp.npsf(srcDir, srcEng.log10TeV(), srcTime, pnt, roi);
test_value(npsf, 1.0, 1.0e-3, "PSF(1,1) integration");
// Test PSF outside and overlapping ROI
srcDir.radec_deg(0.0, 2.0);
npsf = rsp.npsf(srcDir, srcEng.log10TeV(), srcTime, pnt, roi);
test_value(npsf, 0.492373, 1.0e-3, "PSF(0,2) integration");
// Test PSF outside ROI
srcDir.radec_deg(2.0, 2.0);
npsf = rsp.npsf(srcDir, srcEng.log10TeV(), srcTime, pnt, roi);
test_value(npsf, 0.0, 1.0e-3, "PSF(2,2) integration");
// Return
return;
}
/***********************************************************************//**
* @brief Return simulated list of events
*
* @param[in] obs Observation.
* @param[in] ran Random number generator.
* @return Pointer to list of simulated events (needs to be de-allocated by
* client)
*
* @exception GException::invalid_argument
* Specified observation is not a CTA observation.
*
* Draws a sample of events from the background model using a Monte
* Carlo simulation. The region of interest, the energy boundaries and the
* good time interval for the sampling will be extracted from the observation
* argument that is passed to the method. The method also requires a random
* number generator of type GRan which is passed by reference, hence the
* state of the random number generator will be changed by the method.
*
* The method also applies a deadtime correction using a Monte Carlo process,
* taking into account temporal deadtime variations. For this purpose, the
* method makes use of the time dependent GObservation::deadc method.
*
* For each event in the returned event list, the sky direction, the nominal
* coordinates (DETX and DETY), the energy and the time will be set.
***************************************************************************/
GCTAEventList* GCTAModelIrfBackground::mc(const GObservation& obs, GRan& ran) const
{
// Initialise new event list
GCTAEventList* list = new GCTAEventList;
// Continue only if model is valid)
if (valid_model()) {
// Retrieve CTA observation
const GCTAObservation* cta = dynamic_cast<const GCTAObservation*>(&obs);
if (cta == NULL) {
std::string msg = "Specified observation is not a CTA observation.\n" +
obs.print();
throw GException::invalid_argument(G_MC, msg);
}
// Get pointer on CTA IRF response
const GCTAResponseIrf* rsp = dynamic_cast<const GCTAResponseIrf*>(cta->response());
if (rsp == NULL) {
std::string msg = "Specified observation does not contain"
" an IRF response.\n" + obs.print();
throw GException::invalid_argument(G_MC, msg);
}
// Retrieve CTA response and pointing
const GCTAPointing& pnt = cta->pointing();
// Get pointer to CTA background
const GCTABackground* bgd = rsp->background();
if (bgd == NULL) {
std::string msg = "Specified observation contains no background"
" information.\n" + obs.print();
throw GException::invalid_argument(G_MC, msg);
}
// Retrieve event list to access the ROI, energy boundaries and GTIs
const GCTAEventList* events = dynamic_cast<const GCTAEventList*>(obs.events());
if (events == NULL) {
std::string msg = "No CTA event list found in observation.\n" +
obs.print();
throw GException::invalid_argument(G_MC, msg);
}
// Get simulation region
const GCTARoi& roi = events->roi();
const GEbounds& ebounds = events->ebounds();
const GGti& gti = events->gti();
// Set simulation region for result event list
list->roi(roi);
list->ebounds(ebounds);
list->gti(gti);
// Create a spectral model that combines the information from the
// background information and the spectrum provided by the model
GModelSpectralNodes spectral(bgd->spectrum());
for (int i = 0; i < spectral.nodes(); ++i) {
GEnergy energy = spectral.energy(i);
double intensity = spectral.intensity(i);
double norm = m_spectral->eval(energy, events->tstart());
spectral.intensity(i, norm*intensity);
}
// Loop over all energy boundaries
for (int ieng = 0; ieng < ebounds.size(); ++ieng) {
// Compute the background rate in model within the energy
// boundaries from spectral component (units: cts/s).
// Note that the time here is ontime. Deadtime correction will
// be done later.
double rate = spectral.flux(ebounds.emin(ieng), ebounds.emax(ieng));
// Debug option: dump rate
#if defined(G_DUMP_MC)
std::cout << "GCTAModelIrfBackground::mc(\"" << name() << "\": ";
std::cout << "rate=" << rate << " cts/s)" << std::endl;
#endif
// Loop over all good time intervals
for (int itime = 0; itime < gti.size(); ++itime) {
// Get Monte Carlo event arrival times from temporal model
GTimes times = m_temporal->mc(rate,
gti.tstart(itime),
gti.tstop(itime),
ran);
// Get number of events
int n_events = times.size();
// Reserve space for events
if (n_events > 0) {
list->reserve(n_events);
}
// Debug option: provide number of times and initialize
// statisics
#if defined(G_DUMP_MC)
std::cout << " Interval " << itime;
std::cout << " times=" << n_events << std::endl;
int n_killed_by_deadtime = 0;
int n_killed_by_roi = 0;
#endif
// Loop over events
for (int i = 0; i < n_events; ++i) {
// Apply deadtime correction
double deadc = obs.deadc(times[i]);
if (deadc < 1.0) {
if (ran.uniform() > deadc) {
#if defined(G_DUMP_MC)
n_killed_by_deadtime++;
#endif
continue;
}
}
// Get Monte Carlo event energy from spectral model
GEnergy energy = spectral.mc(ebounds.emin(ieng),
ebounds.emax(ieng),
times[i],
ran);
// Get Monte Carlo event direction from spatial model.
// This only will set the DETX and DETY coordinates.
GCTAInstDir instdir = bgd->mc(energy, times[i], ran);
// Derive sky direction from instrument coordinates
GSkyDir skydir = pnt.skydir(instdir);
// Set sky direction in GCTAInstDir object
instdir.dir(skydir);
// Allocate event
GCTAEventAtom event;
// Set event attributes
event.dir(instdir);
event.energy(energy);
event.time(times[i]);
// Append event to list if it falls in ROI
if (events->roi().contains(event)) {
list->append(event);
}
#if defined(G_DUMP_MC)
else {
n_killed_by_roi++;
}
#endif
} // endfor: looped over all events
// Debug option: provide statisics
#if defined(G_DUMP_MC)
std::cout << " Killed by deadtime=";
std::cout << n_killed_by_deadtime << std::endl;
std::cout << " Killed by ROI=";
std::cout << n_killed_by_roi << std::endl;
#endif
} // endfor: looped over all GTIs
} // endfor: looped over all energy boundaries
} // endif: model was valid
// Return
return list;
}
/***********************************************************************//**
* @brief Fill events into counts cube
*
* @param[in] obs CTA observation.
*
* @exception GException::invalid_value
* No event list found in observation.
*
* Fills the events from an event list in the counts cube setup by init_cube.
***************************************************************************/
void ctbin::fill_cube(GCTAObservation* obs)
{
// Continue only if observation pointer is valid
if (obs != NULL) {
// Make sure that the observation holds a CTA event list. If this
// is not the case then throw an exception.
const GCTAEventList* events = dynamic_cast<const GCTAEventList*>(obs->events());
if (events == NULL) {
std::string msg = "CTA Observation does not contain an event "
"list. Event list information is needed to "
"fill the counts map.";
throw GException::invalid_value(G_FILL_CUBE, msg);
}
// Get the RoI
const GCTARoi& roi = events->roi();
// Initialise binning statistics
int num_outside_roi = 0;
int num_outside_map = 0;
int num_outside_ebds = 0;
int num_in_map = 0;
// Fill sky map
for (int i = 0; i < events->size(); ++i) {
// Get event
const GCTAEventAtom* event = (*events)[i];
// Determine sky pixel
GCTAInstDir* inst = (GCTAInstDir*)&(event->dir());
GSkyDir dir = inst->dir();
GSkyPixel pixel = m_cube.dir2pix(dir);
// Skip if pixel is outside RoI
if (roi.centre().dir().dist_deg(dir) > roi.radius()) {
num_outside_roi++;
continue;
}
// Skip if pixel is out of range
if (pixel.x() < -0.5 || pixel.x() > (m_cube.nx()-0.5) ||
pixel.y() < -0.5 || pixel.y() > (m_cube.ny()-0.5)) {
num_outside_map++;
continue;
}
// Determine energy bin. Skip if we are outside the energy range
int index = m_ebounds.index(event->energy());
if (index == -1) {
num_outside_ebds++;
continue;
}
// Fill event in skymap
m_cube(pixel, index) += 1.0;
num_in_map++;
} // endfor: looped over all events
// Append GTIs
m_gti.extend(events->gti());
// Update ontime and livetime
m_ontime += obs->ontime();
m_livetime += obs->livetime();
// Log filling results
if (logTerse()) {
log << gammalib::parformat("Events in list");
log << obs->events()->size() << std::endl;
log << gammalib::parformat("Events in cube");
log << num_in_map << std::endl;
log << gammalib::parformat("Event bins outside RoI");
log << num_outside_roi << std::endl;
log << gammalib::parformat("Events outside cube area");
log << num_outside_map << std::endl;
log << gammalib::parformat("Events outside energy bins");
log << num_outside_ebds << std::endl;
}
// Log cube
if (logExplicit()) {
log.header1("Counts cube");
log << m_cube << std::endl;
}
} // endif: observation was valid
// Return
return;
}
/***********************************************************************//**
* @brief Bin events into a counts map
*
* @param[in] obs CTA observation.
*
* @exception GException::no_list
* No event list found in observation.
* @exception GCTAException::no_pointing
* No valid CTA pointing found.
*
* This method bins the events found in a CTA events list into a counts map
* and replaces the event list by the counts map in the observation. The
* energy boundaries of the counts map are also stored in the observation's
* energy boundary member.
*
* If the reference values for the map centre (m_xref, m_yref) are 9999.0,
* the pointing direction of the observation is taken as the map centre.
* Otherwise, the specified reference value is used.
***************************************************************************/
void ctbin::bin_events(GCTAObservation* obs)
{
// Continue only if observation pointer is valid
if (obs != NULL) {
// Make sure that the observation holds a CTA event list. If this
// is not the case then throw an exception.
if (dynamic_cast<const GCTAEventList*>(obs->events()) == NULL) {
throw GException::no_list(G_BIN_EVENTS);
}
// Setup energy range covered by data
GEnergy emin;
GEnergy emax;
GEbounds ebds;
emin.TeV(m_emin);
emax.TeV(m_emax);
ebds.setlog(emin, emax, m_enumbins);
// Get Good Time intervals
GGti gti = obs->events()->gti();
// Get map centre
double xref;
double yref;
if (m_xref != 9999.0 && m_yref != 9999.0) {
xref = m_xref;
yref = m_yref;
}
else {
// Get pointer on CTA pointing
const GCTAPointing *pnt = obs->pointing();
if (pnt == NULL) {
throw GCTAException::no_pointing(G_BIN_EVENTS);
}
// Set reference point to pointing
if (toupper(m_coordsys) == "GAL") {
xref = pnt->dir().l_deg();
yref = pnt->dir().b_deg();
}
else {
xref = pnt->dir().ra_deg();
yref = pnt->dir().dec_deg();
}
} // endelse: map centre set to pointing
// Create skymap
GSkymap map = GSkymap(m_proj, m_coordsys,
xref, yref, m_binsz, m_binsz,
m_nxpix, m_nypix, m_enumbins);
// Initialise binning statistics
int num_outside_map = 0;
int num_outside_ebds = 0;
int num_in_map = 0;
// Fill sky map
GCTAEventList* events = static_cast<GCTAEventList*>(const_cast<GEvents*>(obs->events()));
for (GCTAEventList::iterator event = events->begin(); event != events->end(); ++event) {
// Determine sky pixel
GCTAInstDir* inst = (GCTAInstDir*)&(event->dir());
GSkyDir dir = inst->dir();
GSkyPixel pixel = map.dir2xy(dir);
// Skip if pixel is out of range
if (pixel.x() < -0.5 || pixel.x() > (m_nxpix-0.5) ||
pixel.y() < -0.5 || pixel.y() > (m_nypix-0.5)) {
num_outside_map++;
continue;
}
// Determine energy bin. Skip if we are outside the energy range
int index = ebds.index(event->energy());
if (index == -1) {
num_outside_ebds++;
continue;
}
// Fill event in skymap
map(pixel, index) += 1.0;
num_in_map++;
} // endfor: looped over all events
// Log binning results
if (logTerse()) {
log << std::endl;
log.header1("Binning");
log << parformat("Events in list");
log << obs->events()->size() << std::endl;
log << parformat("Events in map");
log << num_in_map << std::endl;
log << parformat("Events outside map area");
log << num_outside_map << std::endl;
log << parformat("Events outside energy bins");
log << num_outside_ebds << std::endl;
}
// Log map
if (logTerse()) {
log << std::endl;
log.header1("Counts map");
log << map << std::endl;
}
// Create events cube from sky map
GCTAEventCube cube(map, ebds, gti);
// Replace event list by event cube in observation
obs->events(&cube);
} // endif: observation was valid
// Return
return;
}
/***********************************************************************//**
* @brief Select events
*
* @param[in] obs CTA observation.
* @param[in] filename File name.
*
* Select events from a FITS file by making use of the selection possibility
* of the cfitsio library on loading a file. A selection string is created
* from the specified criteria that is appended to the filename so that
* cfitsio will automatically filter the event data. This selection string
* is then applied when opening the FITS file. The opened FITS file is then
* saved into a temporary file which is the loaded into the actual CTA
* observation, overwriting the old CTA observation. The ROI, GTI and EBounds
* of the CTA event list are then set accordingly to the specified selection.
* Finally, the temporary file created during this process is removed.
*
* Good Time Intervals of the observation will be limited to the time
* interval [m_tmin, m_tmax]. If m_tmin=m_tmax=0, no time selection is
* performed.
*
* @todo Use INDEF instead of 0.0 for pointing as RA/DEC selection
***************************************************************************/
void ctselect::select_events(GCTAObservation* obs, const std::string& filename)
{
// Allocate selection string
std::string selection;
char cmin[80];
char cmax[80];
char cra[80];
char cdec[80];
char crad[80];
// Set requested selections
bool select_time = (m_tmin != 0.0 || m_tmax != 0.0);
// Set RA/DEC selection
double ra = m_ra;
double dec = m_dec;
if (m_usepnt) {
const GCTAPointing *pnt = obs->pointing();
ra = pnt->dir().ra_deg();
dec = pnt->dir().dec_deg();
}
// Set time selection interval. We make sure here that the time selection
// interval cannot be wider than the GTIs covering the data. This is done
// using GGti's reduce() method.
if (select_time) {
// Reduce GTIs to specified time interval. The complicated cast is
// necessary here because the gti() method is declared const, so
// we're not officially allowed to modify the GTIs.
((GGti*)(&obs->events()->gti()))->reduce(m_timemin, m_timemax);
} // endif: time selection was required
// Save GTI for later usage
GGti gti = obs->events()->gti();
// Make time selection
if (select_time) {
// Extract effective time interval in CTA reference time. We need
// this reference for filtering.
double tmin = gti.tstart().convert(m_cta_ref);
double tmax = gti.tstop().convert(m_cta_ref);
// Format time with sufficient accuracy and add to selection string
sprintf(cmin, "%.8f", tmin);
sprintf(cmax, "%.8f", tmax);
selection = "TIME >= "+std::string(cmin)+" && TIME <= "+std::string(cmax);
if (logTerse()) {
log << parformat("Time range");
log << tmin << " - " << tmax << " s" << std::endl;
}
if (selection.length() > 0) {
selection += " && ";
}
}
// Make energy selection
sprintf(cmin, "%.8f", m_emin);
sprintf(cmax, "%.8f", m_emax);
selection += "ENERGY >= "+std::string(cmin)+" && ENERGY <= "+std::string(cmax);
if (logTerse()) {
log << parformat("Energy range");
log << m_emin << " - " << m_emax << " TeV" << std::endl;
}
if (selection.length() > 0) {
selection += " && ";
}
// Make ROI selection
sprintf(cra, "%.6f", ra);
sprintf(cdec, "%.6f", dec);
sprintf(crad, "%.6f", m_rad);
selection += "ANGSEP("+std::string(cra)+"," +
std::string(cdec)+",RA,DEC) <= " +
std::string(crad);
if (logTerse()) {
log << parformat("Acceptance cone centre");
log << "RA=" << ra << ", DEC=" << dec << " deg" << std::endl;
log << parformat("Acceptance cone radius");
log << m_rad << " deg" << std::endl;
}
if (logTerse()) {
log << parformat("cfitsio selection");
log << selection << std::endl;
}
// Add additional expression
if (strip_whitespace(m_expr).length() > 0) {
if (selection.length() > 0) {
selection += " && ";
}
selection += "("+strip_whitespace(m_expr)+")";
}
// Build input filename including selection expression
std::string expression = filename;
if (selection.length() > 0)
expression += "[EVENTS]["+selection+"]";
if (logTerse()) {
log << parformat("FITS filename");
log << expression << std::endl;
}
// Open FITS file
GFits file(expression);
// Log selected FITS file
if (logExplicit()) {
log << std::endl;
log.header1("FITS file content after selection");
log << file << std::endl;
}
// Check if we have an EVENTS HDU
if (!file.hashdu("EVENTS")) {
std::string message = "No \"EVENTS\" extension found in FITS file "+
expression+".";
throw GException::app_error(G_SELECT_EVENTS, message);
}
// Determine number of events in EVENTS HDU
int nevents = file.table("EVENTS")->nrows();
// If the selected event list is empty then append an empty event list
// to the observation. Otherwise load the data from the temporary file.
if (nevents < 1) {
// Create empty event list
GCTAEventList eventlist;
// Append list to observation
obs->events(&eventlist);
}
else {
// Get temporary file name
std::string tmpname = std::tmpnam(NULL);
// Save FITS file to temporary file
file.saveto(tmpname, true);
// Load observation from temporary file
obs->load_unbinned(tmpname);
// Remove temporary file
std::remove(tmpname.c_str());
}
// Get CTA event list pointer
GCTAEventList* list =
static_cast<GCTAEventList*>(const_cast<GEvents*>(obs->events()));
// Set ROI
GCTARoi roi;
GCTAInstDir instdir;
instdir.radec_deg(ra, dec);
roi.centre(instdir);
roi.radius(m_rad);
list->roi(roi);
// Set GTI
list->gti(gti);
// Set energy boundaries
GEbounds ebounds;
GEnergy emin;
GEnergy emax;
emin.TeV(m_emin);
emax.TeV(m_emax);
ebounds.append(emin, emax);
list->ebounds(ebounds);
// Recompute ontime and livetime.
GTime meantime = 0.5 * (gti.tstart() + gti.tstop());
obs->ontime(gti.ontime());
obs->livetime(gti.ontime() * obs->deadc(meantime));
// Return
return;
}