Grid Struct Reference

Structure to contain both source and image trees. More...

#include <grid_maintenance.h>

Collaboration diagram for Grid:

Public Member Functions
	Grid (LensHndl lens, unsigned long N1d, const double center[2], double range)
	Constructor for initializing square grid.
	Grid (LensHndl lens, unsigned long Nx, const PosType center[2], PosType rangeX, PosType rangeY)
	Constructor for initializing rectangular grid.
	~Grid ()
	Destructor for a Grid. Frees all memory.
Grid	ReInitialize (LensHndl lens)
	Returns a new grid that has not been refined but has the same intial image grid, but calculated with a new lens.
void	zoom (LensHndl lens, double *center, double scale, Branch *top=NULL)
	Test if point is in a region of uniform magnification using the kappa and gamma calculated from the rayshooter.
double	RefreshSurfaceBrightnesses (Source *source)
	Reshoot the rays with the same image postions.
double	AddSurfaceBrightnesses (Source *source)
	Recalculate surface brightness just like Grid::RefreshSurfaceBrightness but the new source is added to any sources that were already there.
double	mark_closest_point_source_images (Point_2d y_source, PosType r_source_max, PosType luminosity, bool verbose=false)
	This function finds all the images for a circular source of radius r_source, then finds the points within each image that are closest to the center and then markes each surface brightness. Only one pixel per image gets flux.
void	find_point_source_images (Point_2d y_source, PosType r_source, PosType z_source, std::vector< RAY > &images, bool verbose=false)
	This function finds all the images for a circular source of radius r_source, then finds the points within each image that are closest to the center of the source. Only one pixel per image gets flux. Points are not marked.
double	ClearSurfaceBrightnesses ()
	Reset the surface brightness and in_image flag in every point on image and source planes to zero (false)
double	refine_on_surfacebrightness (Lens &lens, Source &source)
unsigned long	getNumberOfPoints () const
	Returns number of points on image plane.
PosType	EinsteinArea () const
	area of region with negative magnification
int	getInitNgrid ()
	return initial number of grid points in each direction
int	getNgrid_block ()
	return number of cells in each dimension into which each cell is divided when a refinement is made
double	getInitRange ()
	return initial range of gridded region
Point_2d	getInitCenter ()
Point *	RefineLeaf (LensHndl lens, Point *point)
	Fundamental function used to divide a leaf in the tree into nine subcells.
Point *	RefineLeaves (LensHndl lens, std::vector< Point * > &points)
	Same as RefineLeaf() but multiple points can be passed. The rays are shot all together so that more parallelization can be achieved in the rayshooting.
void	ClearAllMarks ()
	Rest all in_image markers to False.
template<typename T >
void	writeFits (const double center[], size_t Npixels, double resolution, LensingVariable lensvar, std::string filename)
	Outputs a fits image of a lensing variable of choice.
template<typename T >
void	writeFits (const double center[], size_t Nx, size_t Ny, double resolution, LensingVariable lensvar, std::string filename)
	Outputs a fits image of a lensing variable of choice.
template<typename T >
void	writeFits (double strech, LensingVariable lensvar, std::string filename)
	make a fits image of whole grid region
template<typename T >
void	writePixelFits (size_t Nx, LensingVariable lensvar, std::string filename)
	Make a fits map that is automatically centered on the grid and has approximately the same range as the grid. Nx can be used to change the resolution. Nx = grid.getInitNgrid() will give the initial grid resolution.
template<typename T >
void	writeFitsVector (const double center[], size_t Npixels, double resolution, LensingVariable lensvar, std::string filename)
	Outputs a fits file for making plots of vector fields.
template<typename T >
PixelMap< T >	writePixelMap (const double center[], size_t Npixels, double resolution, LensingVariable lensvar)
	Outputs a PixelMap of the lensing quantities of a fixed grid.
template<typename T >
PixelMap< T >	writePixelMap (const double center[], size_t Nx, size_t Ny, double resolution, LensingVariable lensvar)
	Outputs a PixelMap of the lensing quantities of a fixed grid.
template<typename T >
PixelMap< T >	writePixelMap (LensingVariable lensvar)
	With the initial boundaries and resolution, ie no refinement.
template<typename T >
void	MapSurfaceBrightness (PixelMap< T > &map)
	make image of surface brightness
template<typename T >
PixelMap< T >	MapSurfaceBrightness (double resolution)
	make a map of the whole gridded area with given resolution
template<typename T >
PixelMap< T >	writePixelMapUniform (const PosType center[], size_t Nx, size_t Ny, LensingVariable lensvar)
	Make a Pixel map of the without distribution the pixels.
template<typename T >
void	writePixelMapUniform (PixelMap< T > &map, LensingVariable lensvar)
template<typename T >
void	writeFitsUniform (const PosType center[], size_t Nx, size_t Ny, LensingVariable lensvar, std::string filename)
	Output a fits map of the without distribution the pixels.
void	find_images (PosType *y_source, PosType r_source, int &Nimages, std::vector< ImageInfo > &imageinfo, unsigned long &Nimagepoints)
	Finds images for a given source position and size. It seporates images of different pairities.
void	map_images (Lens *lens, Source *source, int *Nimages, std::vector< ImageInfo > &imageinfo, PosType xmax, PosType xmin, PosType initial_size, ExitCriterion criterion, bool FindCenter, bool divide_images)
	Find images and refine them based on their surface brightness distribution.
	Grid (Grid &&grid)
Grid	operator= (Grid &grid)=delete
	Grid (Grid &grid)=delete
Grid &	operator= (Grid &&grid)
PosType	magnification (double sblimit=-1.0e12) const
	flux weighted local magnification that does not take multiple imaging into effect
PosType	UnlensedFlux (double sblimit=-1.0e12) const
PosType	LensedFlux (double sblimit=-1.0e12) const
Point_2d	centroid () const
	centroid of flux

Public Attributes
TreeHndl	i_tree
	tree on image plane
TreeHndl	s_tree
	tree on source plane

Detailed Description

Structure to contain both source and image trees.

Constructor & Destructor Documentation

Grid() [1/2]

Grid::Grid	(	LensHndl	lens,
		unsigned long	N1d,
		const double	center[2],
		double	range )

Constructor for initializing square grid.

Note: Deflection solver must be specified before creating a Grid.

Parameters

lens	lens model for initializing grid
N1d	Initial number of grid points in each dimension.
center	Center of grid (usually in radian units)
range	Full width of grid in whatever units will be used.

Grid() [2/2]

Grid::Grid	(	LensHndl	lens,
		unsigned long	Nx,
		const PosType	center[2],
		PosType	rangeX,
		PosType	rangeY )

Constructor for initializing rectangular grid.

Cells of grid will always be square with initial resolution rangeX/(Nx-1). The Y range may not be exactly rangeY, but will be the nearest value that is a whole number of cells.

Note: Deflection solver must be specified before creating a Grid.

Parameters

lens	lens model for initializing grid
Nx	Initial number of grid points in X dimension.
center	Center of grid.
rangeX	Full width of grid in x direction in whatever units will be used.
rangeY	Full width of grid in y direction in whatever units will be used.

Member Function Documentation

AddSurfaceBrightnesses()

PosType Grid::AddSurfaceBrightnesses

(

Source *

source

)

Recalculate surface brightness just like Grid::RefreshSurfaceBrightness but the new source is added to any sources that were already there.

returns the total flux from new source

find_images()

void Grid::find_images	(	PosType *	y_source,
		PosType	r_source,
		int &	Nimages,
		std::vector< ImageInfo > &	imageinfo,
		unsigned long &	Nimagepoints )

Finds images for a given source position and size. It seporates images of different pairities.

No grid refinement is done. If the images is not initially found no nearest neighbor points are returned.

image points are put into imageinfo[].imagekist imageinfo[].points and imageinfo[].Npoints are not changed

side-effects : Will make in_image = true for all image points if splitparities == 0

< >

find_point_source_images()

void Grid::find_point_source_images	(	Point_2d	y_source,
		PosType	r_source,
		PosType	z_source,
		std::vector< RAY > &	images,
		bool	verbose = false )

This function finds all the images for a circular source of radius r_source, then finds the points within each image that are closest to the center of the source. Only one pixel per image gets flux. Points are not marked.

Parameters

y_source	angular position of source,
r_source	points outside this radius on the source plane will not be considered as in the image
z_source	redhsift of source
images	returned image rays

getNumberOfPoints()

unsigned long Grid::getNumberOfPoints

(

)

const

Returns number of points on image plane.

Finding

map_images()

void Grid::map_images	(	Lens *	lens,
		Source *	source,
		int *	Nimages,
		std::vector< ImageInfo > &	imageinfo,
		PosType	xmax,
		PosType	xmin,
		PosType	initial_size,
		ExitCriterion	criterion,
		bool	FindCenter,
		bool	divide_images )

Find images and refine them based on their surface brightness distribution.

Finding

Uses ImageFinding::find_images_kist() to initially find and refine images and then uses a surface brightness based criterion to refine the most important parts of the lens.

map_images is intended for mapping images of sources more complicated than simple circles.

No Grid refinement is done.

mark_closest_point_source_images()

double Grid::mark_closest_point_source_images	(	Point_2d	y_source,
		PosType	r_source_max,
		PosType	luminosity,
		bool	verbose = false )

This function finds all the images for a circular source of radius r_source, then finds the points within each image that are closest to the center and then markes each surface brightness. Only one pixel per image gets flux.

Parameters

y_source	angular position of source,
r_source_max	points outside this radius on the source plane will not be considered as in the image

RefineLeaf()

Point * Grid::RefineLeaf	(	LensHndl	lens,
		Point *	point )

Fundamental function used to divide a leaf in the tree into nine subcells.

Source and image points are created, linked, shot and added to the trees. The leaf pointers of the points including the input are assigned.

If some of the of the points are outside the original grid they will not be added in which case THERE WILL BE LESS THEN Ngrid*Ngrid-1 points added. The true number will be result->head or, if no points are added, result = NULL.

Returns a pointer to the list of image points that have been added. This array can then be used for calculating the surface brightness or marking them as in the image.

i_tree current is left in one of the new subcells.

RefreshSurfaceBrightnesses()

PosType Grid::RefreshSurfaceBrightnesses

(

Source *

source

)

Reshoot the rays with the same image postions.

Finding

The source positions and source tree are updated to the current lens model. The advantage over Grid::ReInitializeGrid() is that the image plane refinements are preserved.

void Grid::ReShoot(LensHndl lens){

PosType range,center[2];

range = i_tree->getTop()->boundary_p2[0] - i_tree->getTop()->boundary_p1[0]; center[0] = (i_tree->getTop()->boundary_p2[0] + i_tree->getTop()->boundary_p1[0])/2; center[1] = (i_tree->getTop()->boundary_p2[1] + i_tree->getTop()->boundary_p1[1])/2;

Grid newgrid(lens,Ngrid_init,center,rangeX,rangeY);

         Grid(LensHndl lens ,unsigned long Nx ,const PosType center[2] ,PosType rangeX ,PosType rangeY);

Point *i_points,*s_points;

unsigned long i;

clear source tree delete s_tree; s_points = NewPointArray(i_tree->pointlist.size()); s_points = point_factory(i_tree->pointlist.size());

build new initial grid PointList::iterator i_tree_pointlist_it; i_tree_pointlist_it.current = i_tree->pointlist.Top(); size_t k; for(i=0,k=0;i<i_tree->pointlist.size();++i){ i_points = *i_tree_pointlist_it; if(i_points->head > 0){

link source and image points for(size_t j=0;j<i_points->head;++j,++k){ i_points[j].image = &s_points[k]; s_points[k].image = &i_points[j]; s_points[k].id = i_points[j].id; s_points[k].gridsize = i_points[j].gridsize; };

{ reshoot the rays std::lock_guard<std::mutex> hold(grid_mutex); lens->rayshooterInternal(i_points->head,i_points); } }

–i_tree_pointlist_it; }

s_tree = new TreeStruct(s_points,s_points->head,1,(i_tree->getTop()->boundary_p2[0] - i_tree->getTop()->boundary_p1[0])/10 ); return; }

Recalculate surface brightness at every point without changing the positions of the grid or any lens properties.

Whatever is in the image is replaced with the one input source. Recalculate the surface brightness at all points on the grid. This is useful when changing the source model while preserving changes in the grid. Both i_tree and s_tree are both changed although only s_tree shows up here.

returns total flux

writeFits() [1/3]

template<typename T >

void Grid::writeFits	(	const double	center[],
		size_t	Npixels,
		double	resolution,
		LensingVariable	lensvar,
		std::string	filename )

Outputs a fits image of a lensing variable of choice.

Parameters

center	center of image
Npixels	number of pixels in image in on dimension
resolution	resolution of image in radians
lensvar	which quantity is to be displayed
filename	file name for image – .kappa.fits, .gamma1.fits, etc will be appended

writeFits() [2/3]

template<typename T >

void Grid::writeFits	(	const double	center[],
		size_t	Nx,
		size_t	Ny,
		double	resolution,
		LensingVariable	lensvar,
		std::string	filename )

Outputs a fits image of a lensing variable of choice.

Parameters

center	center of image
Nx	number of pixels in image in x dimension
Ny	number of pixels in image in y dimension
resolution	resolution of image in radians
lensvar	which quantity is to be displayed
filename	file name for image – .kappa.fits, .gamma1.fits, etc will be appended

writeFits() [3/3]

template<typename T >

void Grid::writeFits	(	double	strech,
		LensingVariable	lensvar,
		std::string	filename )

make a fits image of whole grid region

Parameters

strech	resolution relative to the initial resolution
lensvar	which quantity is to be displayed
filename	file name for image – .kappa.fits, .gamma1.fits, etc will be appended

writeFitsUniform()

template<typename T >

void Grid::writeFitsUniform	(	const PosType	center[],
		size_t	Nx,
		size_t	Ny,
		LensingVariable	lensvar,
		std::string	filename )

Output a fits map of the without distribution the pixels.

This will be faster than Grid::writePixelMap() and Grid::writeFits(). But it puts each grid pixel in one pixelmap pixel and if there are two grid pixels in one pixelmap pixel it uses one at random. This is meant for uniform maps to make equal sized PixelMaps.

Parameters

center	center of image
Nx	number of pixels in image in on dimension
Ny	number of pixels in image in on dimension
lensvar	which quantity is to be displayed
filename	file name for image – .kappa.fits, .gamma1.fits, etc will be appended

writeFitsVector()

template<typename T >

void Grid::writeFitsVector	(	const double	center[],
		size_t	Npixels,
		double	resolution,
		LensingVariable	lensvar,
		std::string	filename )

Outputs a fits file for making plots of vector fields.

Parameters

center	center of image
Npixels	number of pixels in image in on dimension
resolution	resolution of image in radians
lensvar	which quantity is to be displayed
filename	file name for image – .kappa.fits, .gamma1.fits, etc will be appended

writePixelFits()

template<typename T >

void Grid::writePixelFits	(	size_t	Nx,
		LensingVariable	lensvar,
		std::string	filename )

Make a fits map that is automatically centered on the grid and has approximately the same range as the grid. Nx can be used to change the resolution. Nx = grid.getInitNgrid() will give the initial grid resolution.

Parameters

Nx	number of pixels in image in x dimension
lensvar	which quantity is to be displayed
filename	file name for image – .kappa.fits, .gamma1.fits, etc will be appended

writePixelMap() [1/3]

template<typename T >

PixelMap< T > Grid::writePixelMap	(	const double	center[],
		size_t	Npixels,
		double	resolution,
		LensingVariable	lensvar )

Outputs a PixelMap of the lensing quantities of a fixed grid.

Parameters

center	center of image
Npixels	number of pixels in image in on dimension
resolution	resolution of image in radians
lensvar	which quantity is to be displayed

writePixelMap() [2/3]

template<typename T >

PixelMap< T > Grid::writePixelMap	(	const double	center[],
		size_t	Nx,
		size_t	Ny,
		double	resolution,
		LensingVariable	lensvar )

Outputs a PixelMap of the lensing quantities of a fixed grid.

Parameters

center	center of image
Nx	number of pixels in image in on dimension
Ny	number of pixels in image in on dimension
resolution	resolution of image in radians
lensvar	which quantity is to be displayed

writePixelMap() [3/3]

template<typename T >

PixelMap< T > Grid::writePixelMap

(

LensingVariable

lensvar

)

With the initial boundaries and resolution, ie no refinement.

Outputs a PixelMap of the lensing quantities of a fixed grid.

Parameters

lensvar

which quantity is to be displayed

writePixelMapUniform() [1/2]

template<typename T >

PixelMap< T > Grid::writePixelMapUniform	(	const PosType	center[],
		size_t	Nx,
		size_t	Ny,
		LensingVariable	lensvar )

Make a Pixel map of the without distribution the pixels.

This will be faster than Grid::writePixelMap() and Grid::writeFits(). But it puts each grid pixel in one pixelmap pixel and if there are two grid pixels in one pixelmap pixel it uses one at random. This is meant for uniform maps to make equal sized PixelMaps.

Parameters

center	center of image
Nx	number of pixels in image in on dimension
Ny	number of pixels in image in on dimension
lensvar	which quantity is to be displayed

writePixelMapUniform() [2/2]

template<typename T >

void Grid::writePixelMapUniform	(	PixelMap< T > &	map,
		LensingVariable	lensvar )

Parameters

lensvar

which quantity is to be displayed

zoom()

void Grid::zoom	(	LensHndl	lens,
		double *	center,
		double	scale,
		Branch *	top = NULL )

Test if point is in a region of uniform magnification using the kappa and gamma calculated from the rayshooter.

An estimate of the magnification matrix is returned if it returns true. Otherwise the magnification matrix is unspecified.

Magnification matrix elements are considered equal if their difference is smaller than maglimit which is set in the Grid constructor.

quickly refines the grid down to a specific scale at a given point

top is an optional argument that allows for the zooming to start part way down the tree. Default is to start at the root. If the point is not within top or the root nothing is done. The point will not necessarily be in the center of the smallest branch.

Parameters

center	center of point where grid is refined
scale	the smallest grid size to which the grid is refined
top	where on the tree to start, if NULL it will start at the root

---

The documentation for this struct was generated from the following files:

• SLsimLib/include/grid_maintenance.h
• SLsimLib/TreeCode_link/grid_maintenance.cpp
• SLsimLib/TreeCode_link/image_finder.cpp
• SLsimLib/TreeCode_link/map_images.cpp