Esempio n. 1
0
static void sim_baselines(oskar_Simulator* h, DeviceData* d, oskar_Sky* sky,
        int channel_index_block, int time_index_block,
        int time_index_simulation, int* status)
{
    int num_baselines, num_stations, num_src, num_times_block, num_channels;
    double dt_dump_days, t_start, t_dump, gast, frequency, ra0, dec0;
    const oskar_Mem *x, *y, *z;
    oskar_Mem* alias = 0;

    /* Get dimensions. */
    num_baselines   = oskar_telescope_num_baselines(d->tel);
    num_stations    = oskar_telescope_num_stations(d->tel);
    num_src         = oskar_sky_num_sources(sky);
    num_times_block = oskar_vis_block_num_times(d->vis_block);
    num_channels    = oskar_vis_block_num_channels(d->vis_block);

    /* Return if there are no sources in the chunk,
     * or if block time index requested is outside the valid range. */
    if (num_src == 0 || time_index_block >= num_times_block) return;

    /* Get the time and frequency of the visibility slice being simulated. */
    dt_dump_days = h->time_inc_sec / 86400.0;
    t_start = h->time_start_mjd_utc;
    t_dump = t_start + dt_dump_days * (time_index_simulation + 0.5);
    gast = oskar_convert_mjd_to_gast_fast(t_dump);
    frequency = h->freq_start_hz + channel_index_block * h->freq_inc_hz;

    /* Scale source fluxes with spectral index and rotation measure. */
    oskar_sky_scale_flux_with_frequency(sky, frequency, status);

    /* Evaluate station u,v,w coordinates. */
    ra0 = oskar_telescope_phase_centre_ra_rad(d->tel);
    dec0 = oskar_telescope_phase_centre_dec_rad(d->tel);
    x = oskar_telescope_station_true_x_offset_ecef_metres_const(d->tel);
    y = oskar_telescope_station_true_y_offset_ecef_metres_const(d->tel);
    z = oskar_telescope_station_true_z_offset_ecef_metres_const(d->tel);
    oskar_convert_ecef_to_station_uvw(num_stations, x, y, z, ra0, dec0, gast,
            d->u, d->v, d->w, status);

    /* Set dimensions of Jones matrices. */
    if (d->R)
        oskar_jones_set_size(d->R, num_stations, num_src, status);
    if (d->Z)
        oskar_jones_set_size(d->Z, num_stations, num_src, status);
    oskar_jones_set_size(d->J, num_stations, num_src, status);
    oskar_jones_set_size(d->E, num_stations, num_src, status);
    oskar_jones_set_size(d->K, num_stations, num_src, status);

    /* Evaluate station beam (Jones E: may be matrix). */
    oskar_timer_resume(d->tmr_E);
    oskar_evaluate_jones_E(d->E, num_src, OSKAR_RELATIVE_DIRECTIONS,
            oskar_sky_l(sky), oskar_sky_m(sky), oskar_sky_n(sky), d->tel,
            gast, frequency, d->station_work, time_index_simulation, status);
    oskar_timer_pause(d->tmr_E);

#if 0
    /* Evaluate ionospheric phase (Jones Z: scalar) and join with Jones E.
     * NOTE this is currently only a CPU implementation. */
    if (d->Z)
    {
        oskar_evaluate_jones_Z(d->Z, num_src, sky, d->tel,
                &settings->ionosphere, gast, frequency, &(d->workJonesZ),
                status);
        oskar_timer_resume(d->tmr_join);
        oskar_jones_join(d->E, d->Z, d->E, status);
        oskar_timer_pause(d->tmr_join);
    }
#endif

    /* Evaluate parallactic angle (Jones R: matrix), and join with Jones Z*E.
     * TODO Move this into station beam evaluation instead. */
    if (d->R)
    {
        oskar_timer_resume(d->tmr_E);
        oskar_evaluate_jones_R(d->R, num_src, oskar_sky_ra_rad_const(sky),
                oskar_sky_dec_rad_const(sky), d->tel, gast, status);
        oskar_timer_pause(d->tmr_E);
        oskar_timer_resume(d->tmr_join);
        oskar_jones_join(d->R, d->E, d->R, status);
        oskar_timer_pause(d->tmr_join);
    }

    /* Evaluate interferometer phase (Jones K: scalar). */
    oskar_timer_resume(d->tmr_K);
    oskar_evaluate_jones_K(d->K, num_src, oskar_sky_l_const(sky),
            oskar_sky_m_const(sky), oskar_sky_n_const(sky), d->u, d->v, d->w,
            frequency, oskar_sky_I_const(sky),
            h->source_min_jy, h->source_max_jy, status);
    oskar_timer_pause(d->tmr_K);

    /* Join Jones K with Jones Z*E. */
    oskar_timer_resume(d->tmr_join);
    oskar_jones_join(d->J, d->K, d->R ? d->R : d->E, status);
    oskar_timer_pause(d->tmr_join);

    /* Create alias for auto/cross-correlations. */
    oskar_timer_resume(d->tmr_correlate);
    alias = oskar_mem_create_alias(0, 0, 0, status);

    /* Auto-correlate for this time and channel. */
    if (oskar_vis_block_has_auto_correlations(d->vis_block))
    {
        oskar_mem_set_alias(alias,
                oskar_vis_block_auto_correlations(d->vis_block),
                num_stations *
                (num_channels * time_index_block + channel_index_block),
                num_stations, status);
        oskar_auto_correlate(alias, num_src, d->J, sky, status);
    }

    /* Cross-correlate for this time and channel. */
    if (oskar_vis_block_has_cross_correlations(d->vis_block))
    {
        oskar_mem_set_alias(alias,
                oskar_vis_block_cross_correlations(d->vis_block),
                num_baselines *
                (num_channels * time_index_block + channel_index_block),
                num_baselines, status);
        oskar_cross_correlate(alias, num_src, d->J, sky, d->tel,
                d->u, d->v, d->w, gast, frequency, status);
    }

    /* Free alias for auto/cross-correlations. */
    oskar_mem_free(alias, status);
    oskar_timer_pause(d->tmr_correlate);
}
void oskar_sky_evaluate_gaussian_source_parameters(oskar_Sky* sky,
        int zero_failed_sources, double ra0, double dec0, int* num_failed,
        int* status)
{
    int i, j, num_sources;
    int type;

    /* Check if safe to proceed. */
    if (*status) return;

    /* Return if memory is not on the CPU. */
    if (oskar_sky_mem_location(sky) != OSKAR_CPU)
    {
        *status = OSKAR_ERR_BAD_LOCATION;
        return;
    }

    /* Get data type and number of sources. */
    type = oskar_sky_precision(sky);
    num_sources = oskar_sky_num_sources(sky);

    /* Switch on type. */
    if (type == OSKAR_DOUBLE)
    {
        /* Double precision. */
        const double *ra_, *dec_, *maj_, *min_, *pa_;
        double *I_, *Q_, *U_, *V_, *a_, *b_, *c_;
        double cos_pa_2, sin_pa_2, sin_2pa, inv_std_min_2, inv_std_maj_2;
        double ellipse_a, ellipse_b, maj, min, pa, cos_pa, sin_pa, t;
        double l[ELLIPSE_PTS], m[ELLIPSE_PTS];
        double work1[5 * ELLIPSE_PTS], work2[5 * ELLIPSE_PTS];
        double lon[ELLIPSE_PTS], lat[ELLIPSE_PTS];
        double x[ELLIPSE_PTS], y[ELLIPSE_PTS], z[ELLIPSE_PTS];
        ra_  = oskar_mem_double_const(oskar_sky_ra_rad_const(sky), status);
        dec_ = oskar_mem_double_const(oskar_sky_dec_rad_const(sky), status);
        maj_ = oskar_mem_double_const(oskar_sky_fwhm_major_rad_const(sky), status);
        min_ = oskar_mem_double_const(oskar_sky_fwhm_minor_rad_const(sky), status);
        pa_  = oskar_mem_double_const(oskar_sky_position_angle_rad_const(sky), status);
        I_   = oskar_mem_double(oskar_sky_I(sky), status);
        Q_   = oskar_mem_double(oskar_sky_Q(sky), status);
        U_   = oskar_mem_double(oskar_sky_U(sky), status);
        V_   = oskar_mem_double(oskar_sky_V(sky), status);
        a_   = oskar_mem_double(oskar_sky_gaussian_a(sky), status);
        b_   = oskar_mem_double(oskar_sky_gaussian_b(sky), status);
        c_   = oskar_mem_double(oskar_sky_gaussian_c(sky), status);

        for (i = 0; i < num_sources; ++i)
        {
            /* Note: could do something different from the projection below
             * in the case of a line (i.e. maj or min = 0), as in this case
             * there is no ellipse to project, only two points.
             * -- This continue could then be a if() .. else() instead.
             */
            if (maj_[i] == 0.0 && min_[i] == 0.0) continue;

            /* Evaluate shape of ellipse on the l,m plane. */
            ellipse_a = maj_[i]/2.0;
            ellipse_b = min_[i]/2.0;
            cos_pa = cos(pa_[i]);
            sin_pa = sin(pa_[i]);
            for (j = 0; j < ELLIPSE_PTS; ++j)
            {
                t = j * 60.0 * M_PI / 180.0;
                l[j] = ellipse_a*cos(t)*sin_pa + ellipse_b*sin(t)*cos_pa;
                m[j] = ellipse_a*cos(t)*cos_pa - ellipse_b*sin(t)*sin_pa;
            }
            oskar_convert_relative_directions_to_lon_lat_2d_d(ELLIPSE_PTS,
                    l, m, 0.0, 0.0, lon, lat);

            /* Rotate on the sphere. */
            oskar_convert_lon_lat_to_xyz_d(ELLIPSE_PTS, lon, lat, x, y, z);
            oskar_rotate_sph_d(ELLIPSE_PTS, x, y, z, ra_[i], dec_[i]);
            oskar_convert_xyz_to_lon_lat_d(ELLIPSE_PTS, x, y, z, lon, lat);

            oskar_convert_lon_lat_to_relative_directions_2d_d(
                    ELLIPSE_PTS, lon, lat, ra0, dec0, l, m);

            /* Get new major and minor axes and position angle. */
            oskar_fit_ellipse_d(&maj, &min, &pa, ELLIPSE_PTS, l, m, work1,
                    work2, status);

            /* Check if fitting failed. */
            if (*status == OSKAR_ERR_ELLIPSE_FIT_FAILED)
            {
                if (zero_failed_sources)
                {
                    I_[i] = 0.0;
                    Q_[i] = 0.0;
                    U_[i] = 0.0;
                    V_[i] = 0.0;
                }
                ++(*num_failed);
                *status = 0;
                continue;
            }
            else if (*status) break;

            /* Evaluate ellipse parameters. */
            inv_std_maj_2 = 0.5 * (maj * maj) * M_PI_2_2_LN_2;
            inv_std_min_2 = 0.5 * (min * min) * M_PI_2_2_LN_2;
            cos_pa_2 = cos(pa) * cos(pa);
            sin_pa_2 = sin(pa) * sin(pa);
            sin_2pa  = sin(2.0 * pa);
            a_[i] = cos_pa_2*inv_std_min_2     + sin_pa_2*inv_std_maj_2;
            b_[i] = -sin_2pa*inv_std_min_2*0.5 + sin_2pa *inv_std_maj_2*0.5;
            c_[i] = sin_pa_2*inv_std_min_2     + cos_pa_2*inv_std_maj_2;
        }
    }
    else
    {
        /* Single precision. */
        const float *ra_, *dec_, *maj_, *min_, *pa_;
        float *I_, *Q_, *U_, *V_, *a_, *b_, *c_;
        float cos_pa_2, sin_pa_2, sin_2pa, inv_std_min_2, inv_std_maj_2;
        float ellipse_a, ellipse_b, maj, min, pa, cos_pa, sin_pa, t;
        float l[ELLIPSE_PTS], m[ELLIPSE_PTS];
        float work1[5 * ELLIPSE_PTS], work2[5 * ELLIPSE_PTS];
        float lon[ELLIPSE_PTS], lat[ELLIPSE_PTS];
        float x[ELLIPSE_PTS], y[ELLIPSE_PTS], z[ELLIPSE_PTS];
        ra_  = oskar_mem_float_const(oskar_sky_ra_rad_const(sky), status);
        dec_ = oskar_mem_float_const(oskar_sky_dec_rad_const(sky), status);
        maj_ = oskar_mem_float_const(oskar_sky_fwhm_major_rad_const(sky), status);
        min_ = oskar_mem_float_const(oskar_sky_fwhm_minor_rad_const(sky), status);
        pa_  = oskar_mem_float_const(oskar_sky_position_angle_rad_const(sky), status);
        I_   = oskar_mem_float(oskar_sky_I(sky), status);
        Q_   = oskar_mem_float(oskar_sky_Q(sky), status);
        U_   = oskar_mem_float(oskar_sky_U(sky), status);
        V_   = oskar_mem_float(oskar_sky_V(sky), status);
        a_   = oskar_mem_float(oskar_sky_gaussian_a(sky), status);
        b_   = oskar_mem_float(oskar_sky_gaussian_b(sky), status);
        c_   = oskar_mem_float(oskar_sky_gaussian_c(sky), status);

        for (i = 0; i < num_sources; ++i)
        {
            /* Note: could do something different from the projection below
             * in the case of a line (i.e. maj or min = 0), as in this case
             * there is no ellipse to project, only two points.
             * -- This continue could then be a if() .. else() instead.
             */
            if (maj_[i] == 0.0 && min_[i] == 0.0) continue;

            /* Evaluate shape of ellipse on the l,m plane. */
            ellipse_a = maj_[i]/2.0;
            ellipse_b = min_[i]/2.0;
            cos_pa = cos(pa_[i]);
            sin_pa = sin(pa_[i]);
            for (j = 0; j < ELLIPSE_PTS; ++j)
            {
                t = j * 60.0 * M_PI / 180.0;
                l[j] = ellipse_a*cos(t)*sin_pa + ellipse_b*sin(t)*cos_pa;
                m[j] = ellipse_a*cos(t)*cos_pa - ellipse_b*sin(t)*sin_pa;
            }
            oskar_convert_relative_directions_to_lon_lat_2d_f(ELLIPSE_PTS,
                    l, m, 0.0, 0.0, lon, lat);

            /* Rotate on the sphere. */
            oskar_convert_lon_lat_to_xyz_f(ELLIPSE_PTS, lon, lat, x, y, z);
            oskar_rotate_sph_f(ELLIPSE_PTS, x, y, z, ra_[i], dec_[i]);
            oskar_convert_xyz_to_lon_lat_f(ELLIPSE_PTS, x, y, z, lon, lat);

            oskar_convert_lon_lat_to_relative_directions_2d_f(
                    ELLIPSE_PTS, lon, lat, (float)ra0, (float)dec0, l, m);

            /* Get new major and minor axes and position angle. */
            oskar_fit_ellipse_f(&maj, &min, &pa, ELLIPSE_PTS, l, m, work1,
                    work2, status);

            /* Check if fitting failed. */
            if (*status == OSKAR_ERR_ELLIPSE_FIT_FAILED)
            {
                if (zero_failed_sources)
                {
                    I_[i] = 0.0;
                    Q_[i] = 0.0;
                    U_[i] = 0.0;
                    V_[i] = 0.0;
                }
                ++(*num_failed);
                *status = 0;
                continue;
            }
            else if (*status) break;

            /* Evaluate ellipse parameters. */
            inv_std_maj_2 = 0.5 * (maj * maj) * M_PI_2_2_LN_2;
            inv_std_min_2 = 0.5 * (min * min) * M_PI_2_2_LN_2;
            cos_pa_2 = cos(pa) * cos(pa);
            sin_pa_2 = sin(pa) * sin(pa);
            sin_2pa  = sin(2.0 * pa);
            a_[i] = cos_pa_2*inv_std_min_2     + sin_pa_2*inv_std_maj_2;
            b_[i] = -sin_2pa*inv_std_min_2*0.5 + sin_2pa *inv_std_maj_2*0.5;
            c_[i] = sin_pa_2*inv_std_min_2     + cos_pa_2*inv_std_maj_2;
        }
    }
}
int main(int argc, char** argv)
{
    int status = 0;
    oskar::OptionParser opt("oskar_evaulate_pierce_points",
            oskar_version_string());
    opt.add_required("settings file");
    if (!opt.check_options(argc, argv)) return EXIT_FAILURE;

    const char* settings_file = opt.get_arg();

    // Create the log.
    oskar_Log* log = oskar_log_create(OSKAR_LOG_MESSAGE, OSKAR_LOG_STATUS);
    oskar_log_message(log, 'M', 0, "Running binary %s", argv[0]);

    // Enum values used in writing time-freq data binary files
    enum OSKAR_TIME_FREQ_TAGS
    {
        TIME_IDX       = 0,
        FREQ_IDX       = 1,
        TIME_MJD_UTC   = 2,
        FREQ_HZ        = 3,
        NUM_FIELDS     = 4,
        NUM_FIELD_TAGS = 5,
        HEADER_OFFSET  = 10,
        DATA           = 0,
        DIMS           = 1,
        LABEL          = 2,
        UNITS          = 3,
        GRP            = OSKAR_TAG_GROUP_TIME_FREQ_DATA
    };

    oskar_Settings_old settings;
    oskar_settings_old_load(&settings, log, settings_file, &status);
    oskar_log_set_keep_file(log, settings.sim.keep_log_file);
    if (status) return status;

    oskar_Telescope* tel = oskar_settings_to_telescope(&settings, log, &status);
    oskar_Sky* sky = oskar_settings_to_sky(&settings, log, &status);

    // FIXME remove this restriction ... (see evaluate Z)
    if (settings.ionosphere.num_TID_screens != 1)
        return OSKAR_ERR_SETUP_FAIL;

    int type = settings.sim.double_precision ? OSKAR_DOUBLE : OSKAR_SINGLE;
    int loc = OSKAR_CPU;

    int num_sources = oskar_sky_num_sources(sky);
    oskar_Mem *hor_x, *hor_y, *hor_z;
    hor_x = oskar_mem_create(type, loc, num_sources, &status);
    hor_y = oskar_mem_create(type, loc, num_sources, &status);
    hor_z = oskar_mem_create(type, loc, num_sources, &status);

    oskar_Mem *pp_lon, *pp_lat, *pp_rel_path;
    int num_stations = oskar_telescope_num_stations(tel);

    int num_pp = num_stations * num_sources;
    pp_lon = oskar_mem_create(type, loc, num_pp, &status);
    pp_lat = oskar_mem_create(type, loc, num_pp, &status);
    pp_rel_path = oskar_mem_create(type, loc, num_pp, &status);

    // Pierce points for one station (non-owned oskar_Mem pointers)
    oskar_Mem *pp_st_lon, *pp_st_lat, *pp_st_rel_path;
    pp_st_lon = oskar_mem_create_alias(0, 0, 0, &status);
    pp_st_lat = oskar_mem_create_alias(0, 0, 0, &status);
    pp_st_rel_path = oskar_mem_create_alias(0, 0, 0, &status);

    int num_times = settings.obs.num_time_steps;
    double obs_start_mjd_utc = settings.obs.start_mjd_utc;
    double dt_dump = settings.obs.dt_dump_days;

    // Binary file meta-data
    std::string label1 = "pp_lon";
    std::string label2 = "pp_lat";
    std::string label3 = "pp_path";
    std::string units  = "radians";
    std::string units2 = "";
    oskar_Mem *dims = oskar_mem_create(OSKAR_INT, loc, 2, &status);
    /* FIXME is this the correct dimension order ?
     * FIXME get the MATLAB reader to respect dimension ordering */
    oskar_mem_int(dims, &status)[0] = num_sources;
    oskar_mem_int(dims, &status)[1] = num_stations;

    const char* filename = settings.ionosphere.pierce_points.filename;
    oskar_Binary* h = oskar_binary_create(filename, 'w', &status);

    double screen_height_m = settings.ionosphere.TID->height_km * 1000.0;

//    printf("Number of times    = %i\n", num_times);
//    printf("Number of stations = %i\n", num_stations);

    void *x_, *y_, *z_;
    x_ = oskar_mem_void(oskar_telescope_station_true_x_offset_ecef_metres(tel));
    y_ = oskar_mem_void(oskar_telescope_station_true_y_offset_ecef_metres(tel));
    z_ = oskar_mem_void(oskar_telescope_station_true_z_offset_ecef_metres(tel));

    for (int t = 0; t < num_times; ++t)
    {
        double t_dump = obs_start_mjd_utc + t * dt_dump; // MJD UTC
        double gast = oskar_convert_mjd_to_gast_fast(t_dump + dt_dump / 2.0);

        for (int i = 0; i < num_stations; ++i)
        {
            const oskar_Station* station =
                    oskar_telescope_station_const(tel, i);
            double lon = oskar_station_lon_rad(station);
            double lat = oskar_station_lat_rad(station);
            double alt = oskar_station_alt_metres(station);
            double x_ecef, y_ecef, z_ecef, x_offset, y_offset, z_offset;

            if (type == OSKAR_DOUBLE)
            {
                x_offset = ((double*)x_)[i];
                y_offset = ((double*)y_)[i];
                z_offset = ((double*)z_)[i];
            }
            else
            {
                x_offset = (double)((float*)x_)[i];
                y_offset = (double)((float*)y_)[i];
                z_offset = (double)((float*)z_)[i];
            }

            oskar_convert_offset_ecef_to_ecef(1, &x_offset, &y_offset,
                    &z_offset, lon, lat, alt, &x_ecef, &y_ecef, &z_ecef);
            double last = gast + lon;

            if (type == OSKAR_DOUBLE)
            {
                oskar_convert_apparent_ra_dec_to_enu_directions_d(num_sources,
                        oskar_mem_double_const(oskar_sky_ra_rad_const(sky), &status),
                        oskar_mem_double_const(oskar_sky_dec_rad_const(sky), &status),
                        last, lat, oskar_mem_double(hor_x, &status),
                        oskar_mem_double(hor_y, &status),
                        oskar_mem_double(hor_z, &status));
            }
            else
            {
                oskar_convert_apparent_ra_dec_to_enu_directions_f(num_sources,
                        oskar_mem_float_const(oskar_sky_ra_rad_const(sky), &status),
                        oskar_mem_float_const(oskar_sky_dec_rad_const(sky), &status),
                        last, lat, oskar_mem_float(hor_x, &status),
                        oskar_mem_float(hor_y, &status),
                        oskar_mem_float(hor_z, &status));
            }

            int offset = i * num_sources;
            oskar_mem_set_alias(pp_st_lon, pp_lon, offset, num_sources,
                    &status);
            oskar_mem_set_alias(pp_st_lat, pp_lat, offset, num_sources,
                    &status);
            oskar_mem_set_alias(pp_st_rel_path, pp_rel_path, offset,
                    num_sources, &status);
            oskar_evaluate_pierce_points(pp_st_lon, pp_st_lat, pp_st_rel_path,
                    x_ecef, y_ecef, z_ecef, screen_height_m,
                    num_sources, hor_x, hor_y, hor_z, &status);
        } // Loop over stations.

        if (status != 0)
            continue;

        int index = t; // could be = (num_times * f) + t if we have frequency data
        int num_fields = 3;
        int num_field_tags = 4;
        double freq_hz = 0.0;
        int freq_idx = 0;

        // Write the header TAGS
        oskar_binary_write_int(h, GRP, TIME_IDX, index, t, &status);
        oskar_binary_write_double(h, GRP, FREQ_IDX, index, freq_idx, &status);
        oskar_binary_write_double(h, GRP, TIME_MJD_UTC, index, t_dump, &status);
        oskar_binary_write_double(h, GRP, FREQ_HZ, index, freq_hz, &status);
        oskar_binary_write_int(h, GRP, NUM_FIELDS, index, num_fields, &status);
        oskar_binary_write_int(h, GRP, NUM_FIELD_TAGS, index, num_field_tags,
                &status);

        // Write data TAGS (fields)
        int field, tagID;
        field = 0;
        tagID = HEADER_OFFSET + (num_field_tags * field);
        oskar_binary_write_mem(h, pp_lon, GRP, tagID + DATA,
                index, 0, &status);
        oskar_binary_write_mem(h, dims, GRP, tagID  + DIMS,
                index, 0, &status);
        oskar_binary_write(h, OSKAR_CHAR, GRP, tagID + LABEL,
                index, label1.size()+1, label1.c_str(), &status);
        oskar_binary_write(h, OSKAR_CHAR, GRP, tagID + UNITS,
                index, units.size()+1, units.c_str(), &status);
        field = 1;
        tagID = HEADER_OFFSET + (num_field_tags * field);
        oskar_binary_write_mem(h, pp_lat, GRP, tagID + DATA,
                index, 0, &status);
        oskar_binary_write_mem(h, dims, GRP, tagID  + DIMS,
                index, 0, &status);
        oskar_binary_write(h, OSKAR_CHAR, GRP, tagID + LABEL,
                index, label2.size()+1, label2.c_str(), &status);
        oskar_binary_write(h, OSKAR_CHAR, GRP, tagID + UNITS,
                index, units.size()+1, units.c_str(), &status);
        field = 2;
        tagID = HEADER_OFFSET + (num_field_tags * field);
        oskar_binary_write_mem(h, pp_rel_path, GRP, tagID + DATA,
                index, 0, &status);
        oskar_binary_write_mem(h, dims, GRP, tagID  + DIMS,
                index, 0, &status);
        oskar_binary_write(h, OSKAR_CHAR, GRP, tagID + LABEL,
                index, label3.size()+1, label3.c_str(), &status);
        oskar_binary_write(h, OSKAR_CHAR, GRP, tagID + UNITS,
                index, units2.size()+1, units2.c_str(), &status);
    } // Loop over times

    // Close the OSKAR binary file.
    oskar_binary_free(h);

    // clean up memory
    oskar_mem_free(hor_x, &status);
    oskar_mem_free(hor_y, &status);
    oskar_mem_free(hor_z, &status);
    oskar_mem_free(pp_lon, &status);
    oskar_mem_free(pp_lat, &status);
    oskar_mem_free(pp_rel_path, &status);
    oskar_mem_free(pp_st_lon, &status);
    oskar_mem_free(pp_st_lat, &status);
    oskar_mem_free(pp_st_rel_path, &status);
    oskar_mem_free(dims, &status);
    oskar_telescope_free(tel, &status);
    oskar_sky_free(sky, &status);

    // Check for errors.
    if (status)
        oskar_log_error(log, "Run failed: %s.", oskar_get_error_string(status));
    oskar_log_free(log);

    return status;
}