ctmodel.cpp 27.7 KB
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 881 882 883 884 885 886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901 902 903 904 905
/***************************************************************************
 *                  ctmodel - Model cube generation tool                   *
 * ----------------------------------------------------------------------- *
 *  copyright (C) 2012-2017 by Juergen Knoedlseder                         *
 * ----------------------------------------------------------------------- *
 *                                                                         *
 *  This program is free software: you can redistribute it and/or modify   *
 *  it under the terms of the GNU General Public License as published by   *
 *  the Free Software Foundation, either version 3 of the License, or      *
 *  (at your option) any later version.                                    *
 *                                                                         *
 *  This program is distributed in the hope that it will be useful,        *
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of         *
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the          *
 *  GNU General Public License for more details.                           *
 *                                                                         *
 *  You should have received a copy of the GNU General Public License      *
 *  along with this program.  If not, see <http://www.gnu.org/licenses/>.  *
 *                                                                         *
 ***************************************************************************/
/**
 * @file ctmodel.cpp
 * @brief Model cube generation tool implementation
 * @author Juergen Knoedlseder
 */

/* __ Includes ___________________________________________________________ */
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif
#include <cstdio>
#include "ctmodel.hpp"
#include "GTools.hpp"

/* __ Method name definitions ____________________________________________ */
#define G_GET_PARAMETERS                          "ctmodel::get_parameters()"
#define G_FILL_CUBE                    "ctmodel::fill_cube(GCTAObservation*)"

/* __ Debug definitions __________________________________________________ */

/* __ Coding definitions _________________________________________________ */

/* __ Constants __________________________________________________________ */
const GEnergy g_energy_margin(1.0e-12, "TeV");


/*==========================================================================
 =                                                                         =
 =                        Constructors/destructors                         =
 =                                                                         =
 ==========================================================================*/

/***********************************************************************//**
 * @brief Void constructor
 ***************************************************************************/
ctmodel::ctmodel(void) : ctobservation(CTMODEL_NAME, VERSION)
{
    // Initialise members
    init_members();

    // Return
    return;
}


/***********************************************************************//**
 * @brief Observations constructor
 *
 * param[in] obs Observation container.
 *
 * This method creates an instance of the class by copying an existing
 * observations container.
 ***************************************************************************/
ctmodel::ctmodel(const GObservations& obs) :
         ctobservation(CTMODEL_NAME, VERSION, obs)
{
    // Initialise members
    init_members();

    // Return
    return;
}



/***********************************************************************//**
 * @brief Command line constructor
 *
 * @param[in] argc Number of arguments in command line.
 * @param[in] argv Array of command line arguments.
 ***************************************************************************/
ctmodel::ctmodel(int argc, char *argv[]) :
         ctobservation(CTMODEL_NAME, VERSION, argc, argv)
{
    // Initialise members
    init_members();

    // Return
    return;
}


/***********************************************************************//**
 * @brief Copy constructor
 *
 * @param[in] app Application.
 ***************************************************************************/
ctmodel::ctmodel(const ctmodel& app) : ctobservation(app)
{
    // Initialise members
    init_members();

    // Copy members
    copy_members(app);

    // Return
    return;
}


/***********************************************************************//**
 * @brief Destructor
 ***************************************************************************/
ctmodel::~ctmodel(void)
{
    // Free members
    free_members();

    // Return
    return;
}


/*==========================================================================
 =                                                                         =
 =                               Operators                                 =
 =                                                                         =
 ==========================================================================*/

/***********************************************************************//**
 * @brief Assignment operator
 *
 * @param[in] app Application.
 * @return Application.
 ***************************************************************************/
ctmodel& ctmodel::operator=(const ctmodel& app)
{
    // Execute only if object is not identical
    if (this != &app) {

        // Copy base class members
        this->ctobservation::operator=(app);

        // Free members
        free_members();

        // Initialise members
        init_members();

        // Copy members
        copy_members(app);

    } // endif: object was not identical

    // Return this object
    return *this;
}


/*==========================================================================
 =                                                                         =
 =                            Public methods                               =
 =                                                                         =
 ==========================================================================*/

/***********************************************************************//**
 * @brief Clear ctmodel tool
 *
 * Clears ctmodel tool.
 ***************************************************************************/
void ctmodel::clear(void)
{
    // Free members
    free_members();
    this->ctobservation::free_members();
    this->ctool::free_members();

    // Clear base class (needed to conserve tool name and version)
    this->GApplication::clear();

    // Initialise members
    this->ctool::init_members();
    this->ctobservation::init_members();
    init_members();

    // Write header into logger
    log_header();

    // Return
    return;
}


/***********************************************************************//**
 * @brief Generate the model map(s)
 *
 * This method reads the task parameters from the parfile, sets up the
 * observation container, loops over all CTA observations in the container
 * and generates a model map for each CTA observation.
 ***************************************************************************/
void ctmodel::run(void)
{
    // If we're in debug mode then all output is also dumped on the screen
    if (logDebug()) {
        log.cout(true);
    }

    // Get task parameters
    get_parameters();

    // Extract cube properties
    extract_cube_properties();

    // Set energy dispersion flags of all CTA observations and save old
    // values in save_edisp vector
    std::vector<bool> save_edisp = set_edisp(m_obs, m_apply_edisp);

    // Write input observation container into logger
    log_observations(NORMAL, m_obs, "Input observation");

    // Write input model container into logger
    log_models(NORMAL, m_obs.models(), "Input model");

    // Write header
    log_header1(TERSE, "Generate model cube");

    // Loop over all observations in the container
    #pragma omp parallel for
    for (int i = 0; i < m_obs.size(); ++i) {
        
        // Get CTA observation
        GCTAObservation* obs = dynamic_cast<GCTAObservation*>(m_obs[i]);

        // Skip observation if it's not CTA
        if (obs == NULL) {
            log_header3(TERSE, get_obs_header(m_obs[i]));
            std::string msg = " Skipping "+m_obs[i]->instrument()+
                              " observation";
            log_string(NORMAL, msg);
        }

        // Fill cube and leave loop if we are binned mode (meaning we
        // only have one binned observation)
        else if (m_binned) {
            fill_cube(obs);
            i = m_obs.size();
        }

        // Skip observation if we have a binned observation
        else if (obs->eventtype() == "CountsCube") {
            log_header3(TERSE, get_obs_header(m_obs[i]));
            std::string msg = " Skipping binned "+m_obs[i]->instrument()+
                              " observation";
            log_string(NORMAL, msg);
        }

        // Otherwise, everything seems to be fine, so fill the cube from obs
        else {
            // Fill the cube
            fill_cube(obs);
            
            // Dispose events to free memory if event file exists on disk
            if (obs->eventfile().length() > 0 && obs->eventfile().exists()) {
                obs->dispose_events();
            }
        }

    } // endfor: looped over observations

    // Write model cube into header
    log_header1(NORMAL, "Model cube");
    log_string(NORMAL, m_cube.print());

    // Restore energy dispersion flags of all CTA observations
    restore_edisp(m_obs, save_edisp);

    // Optionally publish model cube
    if (m_publish) {
        publish();
    }

    // Return
    return;
}


/***********************************************************************//**
 * @brief Save model cube
 *
 * Saves the model cube into a FITS file specified using the "outfile"
 * task parameter.
 ***************************************************************************/
void ctmodel::save(void)
{
    // Write header
    log_header1(TERSE, "Save model cube");

    // Get model cube filename
    m_outcube = (*this)["outcube"].filename();

    // Save only if filename is non-empty and cube has some size
    if (!m_outcube.is_empty() && m_cube.size() > 0) {
        m_cube.save(m_outcube, clobber());
    }

    // Write into logger what has been done
    std::string fname = (m_outcube.is_empty()) ? "NONE" : m_outcube.url();
    if (m_cube.size() == 0) {
        fname.append(" (cube is empty, no file created)");
    }
    log_value(NORMAL, "Model cube file", fname);

    // Return
    return;
}


/***********************************************************************//**
 * @brief Publish model cube
 *
 * @param[in] name Model cube name.
 ***************************************************************************/
void ctmodel::publish(const std::string& name)
{
    // Write header into logger
    log_header1(TERSE, "Publish model cube");

    // Set default name is user name is empty
    std::string user_name(name);
    if (user_name.empty()) {
        user_name = CTMODEL_NAME;
    }

    // Log filename
    log_value(NORMAL, "Model cube name", user_name);

    // Publish model cube
    m_cube.counts().publish(user_name);

    // Return
    return;
}


/***********************************************************************//**
 * @brief Set model cube
 *
 * @param[in] cube Model cube.
 *
 * Set model cube and set all cube bins to zero.
 ***************************************************************************/
void ctmodel::cube(const GCTAEventCube& cube)
{
    // Set cube
    m_cube = cube;

    // Set all cube bins to zero
    for (int i = 0; i < m_cube.size(); ++i) {
        m_cube[i]->counts(0.0);
    }

    // Signal that cube has been set
    m_has_cube = true;

    // Return
    return;
}


/*==========================================================================
 =                                                                         =
 =                             Private methods                             =
 =                                                                         =
 ==========================================================================*/

/***********************************************************************//**
 * @brief Initialise class members
 ***************************************************************************/
void ctmodel::init_members(void)
{
    // Initialise members
    m_outcube.clear();
    m_apply_edisp = false;
    m_publish     = false;
    m_chatter     = static_cast<GChatter>(2);

    // Initialise protected members
    m_cube.clear();
    m_gti.clear();
    m_has_cube    = false;
    m_append_cube = false;
    m_binned      = false;
    m_dir.clear();
    m_solidangle.clear();
    m_energy.clear();
    m_ewidth.clear();
    m_time.clear();

    // Return
    return;
}


/***********************************************************************//**
 * @brief Copy class members
 *
 * @param[in] app Application.
 ***************************************************************************/
void ctmodel::copy_members(const ctmodel& app)
{
    // Copy attributes
    m_outcube     = app.m_outcube;
    m_apply_edisp = app.m_apply_edisp;
    m_publish     = app.m_publish;
    m_chatter     = app.m_chatter;

    // Copy protected members
    m_cube        = app.m_cube;
    m_gti         = app.m_gti;
    m_has_cube    = app.m_has_cube;
    m_append_cube = app.m_append_cube;
    m_binned      = app.m_binned;
    m_dir         = app.m_dir;
    m_solidangle  = app.m_solidangle;
    m_energy      = app.m_energy;
    m_ewidth      = app.m_ewidth;
    m_time        = app.m_time;

    // Return
    return;
}


/***********************************************************************//**
 * @brief Delete class members
 ***************************************************************************/
void ctmodel::free_members(void)
{
    // Return
    return;
}


/***********************************************************************//**
 * @brief Get application parameters
 *
 * Get all task parameters from parameter file or (if required) by querying
 * the user. The parameters are read in the correct order.
 ***************************************************************************/
void ctmodel::get_parameters(void)
{
    // Reset cube append flag
    m_append_cube = false;

    // If there are no observations in container then load them via user
    // parameters.
    if (m_obs.size() == 0) {
        get_obs();
    }

    // ... otherwise add response information and energy boundaries in case
    // that they are missing
    else {
        setup_observations(m_obs);
    }

    // If we have now excactly one CTA observation (but no cube has yet been
    // appended to the observation) then check whether this observation
    // is a binned observation, and if yes, extract the counts cube for
    // model generation
    if ((m_obs.size() == 1) && (m_append_cube == false)) {

        // Get CTA observation
        GCTAObservation* obs = dynamic_cast<GCTAObservation*>(m_obs[0]);

        // Continue only if observation is a CTA observation
        if (obs != NULL) {

            // Check for binned observation
            if (obs->eventtype() == "CountsCube") {

                // Set cube from binned observation
                GCTAEventCube* evtcube = dynamic_cast<GCTAEventCube*>
                                         (const_cast<GEvents*>(obs->events()));
                cube(*evtcube);

                // Signal that cube has been set
                m_has_cube = true;

                // Signal that we are in binned mode
                m_binned = true;

            } // endif: observation was binned

        } // endif: observation was CTA

    } // endif: had exactly one observation

    // Read model definition file if required
    if (m_obs.models().size() == 0) {

        // Get model filename
        std::string inmodel = (*this)["inmodel"].filename();

        // Load models from file
        m_obs.models(inmodel);

    } // endif: there were no models

    // Get energy dispersion flag parameters
    m_apply_edisp = (*this)["edisp"].boolean();

    // If we do not have yet a counts cube for model computation then check
    // whether we should read it from the "incube" parameter or whether we
    // should create it from scratch using the task parameters
    if (!m_has_cube) {

        // Read cube definition file
        std::string incube = (*this)["incube"].filename();

        // If the cube filename is valid the load the cube and set all cube
        // bins to zero
        if (is_valid_filename(incube)) {

            // Load cube from given file
            m_cube.load(incube);

            // Set all cube bins to zero
            for (int i = 0; i < m_cube.size(); ++i) {
                m_cube[i]->counts(0.0);
            }

        } // endif: cube filename was valid

        // ... otherwise create a cube from the user parameters
        else {
            m_cube = create_cube(m_obs);
        }

        // Signal that cube has been set
        m_has_cube = true;

    } // endif: we had no cube yet

    // Get remaining parameters
    m_publish = (*this)["publish"].boolean();
    m_chatter = static_cast<GChatter>((*this)["chatter"].integer());

    // Read optionally output cube filenames
    if (read_ahead()) {
        m_outcube = (*this)["outcube"].filename();
    }

    // If cube should be appended to first observation then do that now.
    // This is a kluge that makes sure that the cube is passed as part
    // of the observation in case that a cube response is used. The kluge
    // is needed because the GCTACubeSourceDiffuse::set method needs to
    // get the full event cube from the observation. It is also at this
    // step that the GTI, which may just be a dummy GTI when create_cube()
    // has been used, will be set.
    if (m_append_cube) {

        //TODO: Check that energy boundaries are compatible

        // Attach GTI of observations to model cube
        m_cube.gti(m_obs[0]->events()->gti());
    
        // Attach model cube to observations
        m_obs[0]->events(m_cube);

    } // endif: cube was scheduled for appending

    // Write parameters into logger
    log_parameters(TERSE);

    // Return
    return;
}


/***********************************************************************//**
 * @brief Get observation container
 *
 * Get an observation container according to the user parameters. The method
 * supports loading of a individual FITS file or an observation definition
 * file in XML format.
 *
 * If the input filename is empty, the method checks for the existence of the
 * "expcube", "psfcube" and "bkgcube" parameters. If file names have been
 * specified, the method loads the files and creates a dummy events cube that
 * is appended to the observation container.
 *
 * If no file names are specified for the "expcube", "psfcube" or "bkgcube"
 * parameters, the method reads the necessary parameters to build a CTA
 * observation from scratch.
 *
 * The method sets m_append_cube = true and m_binned = true in case that
 * a stacked observation is requested (as detected by the presence of the
 * "expcube", "psfcube", and "bkgcube" parameters). In that case, it appended
 * a dummy event cube to the observation.
 *
 * @todo Support stacked energy dispersion
 ***************************************************************************/
void ctmodel::get_obs(void)
{
    // Get the filename from the input parameters
    std::string filename = (*this)["inobs"].filename();

    // If no observation definition file has been specified then read all
    // parameters that are necessary to create an observation from scratch
    if (!is_valid_filename(filename)) {

        // Get response cube filenames
        std::string expcube = (*this)["expcube"].filename();
        std::string psfcube = (*this)["psfcube"].filename();
        std::string bkgcube = (*this)["bkgcube"].filename();

        // If the filenames are valid then build an observation from cube
        // response information
        if (is_valid_filename(expcube) && is_valid_filename(psfcube) &&
            is_valid_filename(bkgcube)) {

            // Get exposure, PSF and background cubes
            GCTACubeExposure   exposure(expcube);
            GCTACubePsf        psf(psfcube);
            GCTACubeBackground background(bkgcube);

            // Create energy boundaries
            GEbounds ebounds = create_ebounds();

            // Create dummy sky map cube
            GSkyMap map("CAR","GAL",0.0,0.0,1.0,1.0,1,1,ebounds.size());

            // Create event cube
            GCTAEventCube cube(map, ebounds, exposure.gti());

            // Create CTA observation
            GCTAObservation cta;
            cta.events(cube);
            cta.response(exposure, psf, background);

            // Append observation to container
            m_obs.append(cta);

            // Signal that we are in binned mode
            m_binned = true;

            // Signal that we appended a cube
            m_append_cube = true;

        } // endif: cube response information was available

        // ... otherwise build an observation from IRF response information
        else {

            // Create CTA observation
            GCTAObservation cta = create_cta_obs();

            // Set response
            set_obs_response(&cta);

            // Append observation to container
            m_obs.append(cta);

        }

    } // endif: filename was not valid

    // ... otherwise we have a file name
    else {

        // If file is a FITS file then create an empty CTA observation
        // and load file into observation
        if (GFilename(filename).is_fits()) {

            // Allocate empty CTA observation
            GCTAObservation cta;

            // Load data
            cta.load(filename);

            // Set response
            set_obs_response(&cta);

            // Append observation to container
            m_obs.append(cta);

            // Signal that no XML file should be used for storage
            m_use_xml = false;

        }

        // ... otherwise load file into observation container
        else {

            // Load observations from XML file
            m_obs.load(filename);

            // For all observations that have no response, set the response
            // from the task parameters
            set_response(m_obs);

            // Set observation boundary parameters (emin, emax, rad)
            set_obs_bounds(m_obs);

            // Signal that XML file should be used for storage
            m_use_xml = true;

        } // endelse: file was an XML file

    }

    // Return
    return;

}


/***********************************************************************//**
 * @brief Extract cube properties in data members
 ***************************************************************************/
void ctmodel::extract_cube_properties(void)
{
    // Clear cube properties
    m_dir.clear();
    m_solidangle.clear();
    m_energy.clear();
    m_ewidth.clear();

    // Get number of spatial pixels and energy layers in counts cube
    int npix   = m_cube.npix();
    int nebins = m_cube.ebins();

    // Reserve capacity in vectors
    m_dir.reserve(npix);
    m_solidangle.reserve(npix);
    m_energy.reserve(nebins);
    m_ewidth.reserve(nebins);

    // Loop over all the spatial bins and extract spatial cube properties
    for (int i = 0; i < npix; ++i) {

        // Get cube bin
        GCTAEventBin* bin = m_cube[i];

        // Extract sky direction and solid angle
        m_dir.push_back(bin->dir());
        m_solidangle.push_back(bin->solidangle());

    } // endfor: looped over spatial bins

    // Loop over all the spectral bins and extract spectral cube properties
    for (int iebin = 0, ibin = 0; iebin < nebins; ++iebin, ibin += npix) {

        // Get cube bin
        GCTAEventBin* bin = m_cube[ibin];

        // Extract energy and energy width
        m_energy.push_back(bin->energy());
        m_ewidth.push_back(bin->ewidth());

    } // endfor: looped over spectral bins

    // Set time
    m_time = m_cube[0]->time();

    // Return
    return;
}


/***********************************************************************//**
 * @brief Fill model into model cube
 *
 * @param[in] obs CTA observation.
 *
 * Adds the expected number of events for a given observation to the events
 * that are already found in the model cube. The method also updates the
 * GTI of the model cube so that cube GTI is a list of the GTIs of all
 * observations that were used to generate the model cube.
 ***************************************************************************/
void ctmodel::fill_cube(const GCTAObservation* obs)
{
    // Get number of spatial and spectral bins in counts cube
    int npix   = m_cube.npix();
    int nebins = m_cube.ebins();

    // Get references to GTI and energy boundaries for the event list
    const GGti&     gti         = obs->events()->gti();
    const GEbounds& obs_ebounds = obs->ebounds();

    // Get cube energy boundaries
    const GEbounds& cube_ebounds = m_cube.ebounds();

    // Get counts cube usage flags
    std::vector<bool> usage = cube_layer_usage(cube_ebounds, obs_ebounds);

    // Initialise empty, invalid RoI
    GCTARoi roi;

    // Retrieve RoI in case we have an unbinned observation
    if (obs->eventtype() == "EventList") {
        roi = obs->roi();
    }

    // Initialise statistics
    double sum              = 0.0;
    int    num_outside_ebds = 0;
    int    num_outside_roi  = 0;

    // Extract copy of models from observation container
    GModels models(m_obs.models());

    // Get pointer to event cube pixels
    double* pixels = const_cast<double*>(m_cube.counts().pixels());

    // Initialise event bin
    GCTAEventBin bin;

    // Set event bin attributes that are constant for a counts cube
    bin.time(m_time);
    bin.ontime(obs->ontime());
    bin.weight(1.0);

    // Loop over all the spatial bins
    for (int i = 0; i < npix; ++i) {

        // If RoI is valid then skip bin if it is outside the RoI of the
        // observation
        if (roi.is_valid() && !roi.contains(m_dir[i])) {
            num_outside_roi += nebins;
            continue;
        }

        // Set instrument direction and solid angle of bin
        bin.dir(m_dir[i]);
        bin.solidangle(m_solidangle[i]);

        // Loop over all of the energy bins of the cube
        for (int iebin = 0, ibin = i; iebin < nebins; ++iebin, ibin += npix) {

            // Skip bin if the corresponding counts cube energy bin is not fully
            // contained in the event list energy range. This avoids having
            // partially filled bins.
            if (!usage[iebin]) {
                num_outside_ebds++;
                continue;
            }

            // Set energy and energy width of bin
            bin.energy(m_energy[iebin]);
            bin.ewidth(m_ewidth[iebin]);

            // Compute model value for cube bin
            double model = models.eval(bin, *obs) * bin.size();

            // Sum model
            sum += model;

            // Store value
            #pragma omp critical(ctmodel_fill_cube)
            pixels[ibin] += model;

        } // endfor: looped over all spatial bins

    } // endfor: looped over all cube bins

    // Update GTIs
    #pragma omp critical(ctmodel_fill_cube)
    {
        // Append GTIs of observation to list of GTIs
        m_gti.extend(gti);

        // Update GTIs
        m_cube.gti(m_gti);
    }

    // Log filling results
    #pragma omp critical(ctmodel_fill_cube)
    {
        log_header3(TERSE, get_obs_header(obs));
        log_value(NORMAL, "Model events in cube", sum);
        log_value(NORMAL, "Bins outside energy range", num_outside_ebds);
        log_value(NORMAL, "Bins outside RoI", num_outside_roi);
    }

    // Write model cube into header
    if (m_chatter >= EXPLICIT) {
        log_header2(EXPLICIT, "Model cube");
        log_string(EXPLICIT, m_cube.print(m_chatter));
    }

    // Return
    return;
}