/***********************************************************************//**
* @brief Computes the maximum radius (in degrees) around a given source
* direction that fits spatially into the event cube
*
* @param[in] srcDir Source direction.
* @return Maximum radius in degrees that fully fits into event cube.
*
* By computing the sky directions of the event cube boundaries, the maximum
* radius is computed that fits fully within the event cube. This method is
* used for PSF normalization.
***************************************************************************/
double GLATEventCube::maxrad(const GSkyDir& srcDir) const
{
// Initialise radius
double radius = 0.0;
// Continue only if sky direction is within sky map
if (m_map.contains(srcDir)) {
// Set to largest possible radius
radius = 180.0;
// Move along upper edge in longitude
int iy = 0;
for (int ix = 0; ix < nx(); ++ix) {
GSkyPixel pixel = GSkyPixel(double(ix), double(iy));
double distance = m_map.pix2dir(pixel).dist_deg(srcDir);
if (distance < radius) {
radius = distance;
}
}
// Move along lower edge in longitude
iy = ny()-1;
for (int ix = 0; ix < nx(); ++ix) {
GSkyPixel pixel = GSkyPixel(double(ix), double(iy));
double distance = m_map.pix2dir(pixel).dist_deg(srcDir);
if (distance < radius) {
radius = distance;
}
}
// Move along left edge in latitude
int ix = 0;
for (int iy = 0; iy < ny(); ++iy) {
GSkyPixel pixel = GSkyPixel(double(ix), double(iy));
double distance = m_map.pix2dir(pixel).dist_deg(srcDir);
if (distance < radius) {
radius = distance;
}
}
// Move along right edge in latitude
ix = nx()-1;
for (int iy = 0; iy < ny(); ++iy) {
GSkyPixel pixel = GSkyPixel(double(ix), double(iy));
double distance = m_map.pix2dir(pixel).dist_deg(srcDir);
if (distance < radius) {
radius = distance;
}
}
} // endif: sky direction within sky map
// Return radius
return radius;
}
/***********************************************************************//**
* @brief Computes the maximum radius (in degrees) around a given source
* direction that fits spatially into the event cube
*
* @param[in] srcDir Source direction.
* @return Maximum radius in degrees that fully fits into event cube.
*
* By computing the sky directions of the event cube boundaries, the maximum
* radius is computed that fits fully within the event cube. This method is
* used for PSF normalization.
***************************************************************************/
double GLATEventCube::maxrad(const GSkyDir& srcDir) const
{
// Initialise radius
double radius = 180.0;
// Move along upper edge in longitude
int iy = 0;
for (int ix = 0; ix < nx(); ++ix) {
GSkyPixel pixel = GSkyPixel(double(ix), double(iy));
double distance = m_map.pix2dir(pixel).dist_deg(srcDir);
if (distance < radius) {
radius = distance;
}
}
// Move along lower edge in longitude
iy = ny()-1;
for (int ix = 0; ix < nx(); ++ix) {
GSkyPixel pixel = GSkyPixel(double(ix), double(iy));
double distance = m_map.pix2dir(pixel).dist_deg(srcDir);
if (distance < radius) {
radius = distance;
}
}
// Move along left edge in latitude
int ix = 0;
for (int iy = 0; iy < ny(); ++iy) {
GSkyPixel pixel = GSkyPixel(double(ix), double(iy));
double distance = m_map.pix2dir(pixel).dist_deg(srcDir);
if (distance < radius) {
radius = distance;
}
}
// Move along right edge in latitude
ix = nx()-1;
for (int iy = 0; iy < ny(); ++iy) {
GSkyPixel pixel = GSkyPixel(double(ix), double(iy));
double distance = m_map.pix2dir(pixel).dist_deg(srcDir);
if (distance < radius) {
radius = distance;
}
}
// Return radius
return radius;
}
/***********************************************************************//**
* @brief Set sky directions and solid angles of events cube.
*
* @exception GLATException::no_sky
* No sky pixels found in event cube.
*
* This method computes the sky directions and solid angles for all event
* cube pixels. Sky directions are stored in an array of GLATInstDir objects
* while solid angles are stored in units of sr in a double precision array.
***************************************************************************/
void GLATEventCube::set_directions(void)
{
// Throw an error if we have no sky pixels
if (npix() < 1) {
throw GLATException::no_sky(G_SET_DIRECTIONS, "Every LAT event cube"
" needs a definition of the sky pixels.");
}
// Clear old pixel directions and solid angle
m_dirs.clear();
m_solidangle.clear();
// Reserve space for pixel directions and solid angles
m_dirs.reserve(npix());
m_solidangle.reserve(npix());
// Set pixel directions and solid angles
for (int iy = 0; iy < ny(); ++iy) {
for (int ix = 0; ix < nx(); ++ix) {
GSkyPixel pixel = GSkyPixel(double(ix), double(iy));
m_dirs.push_back(GLATInstDir(m_map.pix2dir(pixel)));
m_solidangle.push_back(m_map.solidangle(pixel));
}
}
// Return
return;
}
