static void evaluate_station_beam_enu_directions(oskar_Mem* beam_pattern,
int np, const oskar_Mem* x, const oskar_Mem* y, const oskar_Mem* z,
const oskar_Station* station, oskar_StationWork* work,
int time_index, double frequency_hz, double GAST, int* status)
{
if (*status) return;
switch (oskar_station_type(station))
{
case OSKAR_STATION_TYPE_AA:
{
oskar_evaluate_station_beam_aperture_array(beam_pattern, station,
np, x, y, z, GAST, frequency_hz, work, time_index, status);
break;
}
case OSKAR_STATION_TYPE_ISOTROPIC:
{
oskar_mem_set_value_real(beam_pattern, 1.0, 0, np, status);
break;
}
case OSKAR_STATION_TYPE_GAUSSIAN_BEAM:
{
oskar_Mem *l, *m, *n; /* Relative direction cosines */
double fwhm, f0;
l = oskar_station_work_enu_direction_x(work);
m = oskar_station_work_enu_direction_y(work);
n = oskar_station_work_enu_direction_z(work);
compute_relative_directions(l, m, n, np, x, y, z, station, GAST,
status);
fwhm = oskar_station_gaussian_beam_fwhm_rad(station);
f0 =oskar_station_gaussian_beam_reference_freq_hz(station);
fwhm *= f0 / frequency_hz;
oskar_evaluate_station_beam_gaussian(beam_pattern, np, l, m, z,
fwhm, status);
break;
}
case OSKAR_STATION_TYPE_VLA_PBCOR:
{
oskar_Mem *l, *m, *n; /* Relative direction cosines */
l = oskar_station_work_enu_direction_x(work);
m = oskar_station_work_enu_direction_y(work);
n = oskar_station_work_enu_direction_z(work);
compute_relative_directions(l, m, n, np, x, y, z, station, GAST,
status);
oskar_evaluate_vla_beam_pbcor(beam_pattern, np, l, m, frequency_hz,
status);
break;
}
default:
{
*status = OSKAR_ERR_SETTINGS_TELESCOPE;
break;
}
};
}
void oskar_evaluate_station_beam(oskar_Mem* beam_pattern, int num_points,
int coord_type, oskar_Mem* x, oskar_Mem* y, oskar_Mem* z,
double norm_ra_rad, double norm_dec_rad, const oskar_Station* station,
oskar_StationWork* work, int time_index, double frequency_hz,
double GAST, int* status)
{
int normalise_final_beam;
oskar_Mem* out;
/* Check if safe to proceed. */
if (*status) return;
/* Set default output beam array. */
out = beam_pattern;
/* Check that the arrays have enough space to add an extra source at the
* end (for normalisation). We don't want to reallocate here, since that
* will be slow to do each time: must simply ensure that we pass input
* arrays that are large enough.
* The normalisation doesn't need to happen if the station has an
* isotropic beam. */
normalise_final_beam = oskar_station_normalise_final_beam(station) &&
(oskar_station_type(station) != OSKAR_STATION_TYPE_ISOTROPIC);
if (normalise_final_beam)
{
double c_x = 0.0, c_y = 0.0, c_z = 1.0;
/* Increment number of points. */
num_points++;
/* Check the input arrays are big enough to hold the new source. */
if ((int)oskar_mem_length(x) < num_points ||
(int)oskar_mem_length(y) < num_points ||
(int)oskar_mem_length(z) < num_points)
{
*status = OSKAR_ERR_DIMENSION_MISMATCH;
return;
}
/* Set output beam array to work buffer. */
out = oskar_station_work_normalised_beam(work, beam_pattern, status);
/* Get the beam direction in the appropriate coordinate system. */
/* (Direction cosines are already set to the interferometer phase
* centre for relative directions.) */
if (coord_type == OSKAR_ENU_DIRECTIONS)
{
double t_x, t_y, t_z, ha0;
ha0 = (GAST + oskar_station_lon_rad(station)) - norm_ra_rad;
oskar_convert_relative_directions_to_enu_directions_d(
&t_x, &t_y, &t_z, 1, &c_x, &c_y, &c_z, ha0, norm_dec_rad,
oskar_station_lat_rad(station));
c_x = t_x;
c_y = t_y;
c_z = t_z;
}
/* Add the extra normalisation source to the end of the arrays. */
oskar_mem_set_element_real(x, num_points-1, c_x, status);
oskar_mem_set_element_real(y, num_points-1, c_y, status);
oskar_mem_set_element_real(z, num_points-1, c_z, status);
}
/* Evaluate the station beam for the given directions. */
if (coord_type == OSKAR_ENU_DIRECTIONS)
{
evaluate_station_beam_enu_directions(out, num_points, x, y, z,
station, work, time_index, frequency_hz, GAST, status);
}
else if (coord_type == OSKAR_RELATIVE_DIRECTIONS)
{
evaluate_station_beam_relative_directions(out, num_points, x, y, z,
station, work, time_index, frequency_hz, GAST, status);
}
else
{
*status = OSKAR_ERR_INVALID_ARGUMENT;
}
/* Scale beam pattern by value of the last source if required. */
if (normalise_final_beam)
{
double amp = 0.0;
/* Get the last element of the vector and convert to amplitude. */
if (oskar_mem_is_matrix(out))
{
double4c val;
val = oskar_mem_get_element_matrix(out, num_points-1, status);
/*
* Scale by square root of "Stokes I" autocorrelation:
* sqrt(0.5 * [sum of resultant diagonal]).
*
* We have
* [ Xa Xb ] [ Xa* Xc* ] = [ Xa Xa* + Xb Xb* (don't care) ]
* [ Xc Xd ] [ Xb* Xd* ] [ (don't care) Xc Xc* + Xd Xd* ]
*
* Stokes I is completely real, so need only evaluate the real
* part of all the multiplies. Because of the conjugate terms,
* these become re*re + im*im.
*
* Need the square root because we only want the normalised value
* for the beam itself (in isolation), not its actual
* autocorrelation!
*/
amp = val.a.x * val.a.x + val.a.y * val.a.y +
val.b.x * val.b.x + val.b.y * val.b.y +
val.c.x * val.c.x + val.c.y * val.c.y +
val.d.x * val.d.x + val.d.y * val.d.y;
amp = sqrt(0.5 * amp);
}
else
{
double2 val;
val = oskar_mem_get_element_complex(out, num_points-1, status);
/* Scale by voltage. */
amp = sqrt(val.x * val.x + val.y * val.y);
}
/* Scale beam array by normalisation value. */
oskar_mem_scale_real(out, 1.0/amp, status);
/* Copy output beam data. */
oskar_mem_copy_contents(beam_pattern, out, 0, 0, num_points-1, status);
}
}
void oskar_evaluate_station_beam(int num_points,
int coord_type, oskar_Mem* x, oskar_Mem* y, oskar_Mem* z,
double norm_ra_rad, double norm_dec_rad, const oskar_Station* station,
oskar_StationWork* work, int time_index, double frequency_hz,
double GAST, int offset_out, oskar_Mem* beam, int* status)
{
oskar_Mem* out;
const size_t num_points_orig = (size_t)num_points;
if (*status) return;
/* Set output beam array to work buffer. */
out = oskar_station_work_beam_out(work, beam, num_points_orig, status);
/* Check that the arrays have enough space to add an extra source at the
* end (for normalisation). We don't want to reallocate here, since that
* will be slow to do each time: must simply ensure that we pass input
* arrays that are large enough.
* The normalisation doesn't need to happen if the station has an
* isotropic beam. */
const int normalise = oskar_station_normalise_final_beam(station) &&
(oskar_station_type(station) != OSKAR_STATION_TYPE_ISOTROPIC);
if (normalise)
{
/* Increment number of points. */
num_points++;
/* Check the input arrays are big enough to hold the new source. */
if ((int)oskar_mem_length(x) < num_points ||
(int)oskar_mem_length(y) < num_points ||
(int)oskar_mem_length(z) < num_points)
{
*status = OSKAR_ERR_DIMENSION_MISMATCH;
return;
}
/* Get the beam direction in the appropriate coordinate system. */
const int bypass = (coord_type != OSKAR_ENU_DIRECTIONS);
const double ha0 = GAST + oskar_station_lon_rad(station) - norm_ra_rad;
const double lat = oskar_station_lat_rad(station);
oskar_convert_relative_directions_to_enu_directions(1, bypass, 0,
1, 0, 0, 0, ha0, norm_dec_rad, lat, num_points - 1, x, y, z,
status);
}
/* Evaluate the station beam for the given directions. */
if (coord_type == OSKAR_ENU_DIRECTIONS)
evaluate_station_beam_enu_directions(out, num_points, x, y, z,
station, work, time_index, frequency_hz, GAST, status);
else if (coord_type == OSKAR_RELATIVE_DIRECTIONS)
evaluate_station_beam_relative_directions(out, num_points, x, y, z,
station, work, time_index, frequency_hz, GAST, status);
else
*status = OSKAR_ERR_INVALID_ARGUMENT;
/* Scale beam pattern by amplitude at the last source if required. */
if (normalise)
oskar_mem_normalise(out, 0, oskar_mem_length(out),
num_points - 1, status);
/* Copy output beam data. */
oskar_mem_copy_contents(beam, out, offset_out, 0, num_points_orig, status);
}
