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;
}
}
}
TEST(fit_ellipse, test1)
{
int num_points = 7, status = 0;
double maj_d = 0.0, min_d = 0.0, pa_d = 0.0;
float maj_f = 0.0, min_f = 0.0, pa_f = 0.0;
// Test double precision.
{
std::vector<double> x(num_points), y(num_points);
std::vector<double> work1(5 * num_points), work2(5 * num_points);
x[0] = -0.1686;
x[1] = -0.0921;
x[2] = 0.0765;
x[3] = 0.1686;
x[4] = 0.0921;
x[5] = -0.0765;
x[6] = -0.1686;
y[0] = 0.7282;
y[1] = 0.6994;
y[2] = 0.6675;
y[3] = 0.6643;
y[4] = 0.7088;
y[5] = 0.7407;
y[6] = 0.7282;
oskar_fit_ellipse_d(&maj_d, &min_d, &pa_d, num_points, &x[0], &y[0],
&work1[0], &work2[0], &status);
EXPECT_EQ(0, status) << oskar_get_error_string(status);
}
// Test single precision.
{
std::vector<float> x(num_points), y(num_points);
std::vector<float> work1(5 * num_points), work2(5 * num_points);
x[0] = -0.1686;
x[1] = -0.0921;
x[2] = 0.0765;
x[3] = 0.1686;
x[4] = 0.0921;
x[5] = -0.0765;
x[6] = -0.1686;
y[0] = 0.7282;
y[1] = 0.6994;
y[2] = 0.6675;
y[3] = 0.6643;
y[4] = 0.7088;
y[5] = 0.7407;
y[6] = 0.7282;
oskar_fit_ellipse_f(&maj_f, &min_f, &pa_f, num_points, &x[0], &y[0],
&work1[0], &work2[0], &status);
EXPECT_EQ(0, status) << oskar_get_error_string(status);
}
// Compare results.
EXPECT_NEAR(maj_d, 0.3608619735, 1e-9);
EXPECT_NEAR(min_d, 0.0494223702, 1e-9);
EXPECT_NEAR(pa_d, -1.3865537748, 1e-9);
EXPECT_NEAR(maj_d, maj_f, 1e-5);
EXPECT_NEAR(min_d, min_f, 1e-5);
EXPECT_NEAR(pa_d, pa_f, 1e-5);
}