A "combinatorial dimension" geometry. More...

#include <egs_cd_geometry.h>

Inheritance diagram for EGS_CDGeometry:

Public Member Functions
	EGS_CDGeometry (EGS_BaseGeometry G1, EGS_BaseGeometry *G, const string &Name="", int indexing=0)

	EGS_CDGeometry (EGS_BaseGeometry G1, const vector< EGS_BaseGeometry > &G, const string &Name="", int indexing=0)

int	medium (int ireg) const

bool	isRealRegion (int ireg) const

bool	isInside (const EGS_Vector &x)

int	isWhere (const EGS_Vector &x)

int	inside (const EGS_Vector &x)

int	howfar (int ireg, const EGS_Vector &x, const EGS_Vector &u, EGS_Float &t, int newmed=0, EGS_Vector normal=0)

EGS_Float	hownear (int ireg, const EGS_Vector &x)

int	getMaxStep () const

bool	hasBooleanProperty (int ireg, EGS_BPType prop) const

void	setBooleanProperty (EGS_BPType)

void	addBooleanProperty (int)

void	setBooleanProperty (EGS_BPType, int, int, int step=1)

void	addBooleanProperty (int, int, int, int step=1)

const string &	getType () const

void	setRelativeRho (int start, int end, EGS_Float rho)

void	setRelativeRho (EGS_Input *)

EGS_Float	getRelativeRho (int ireg) const

void	setBScaling (int start, int end, EGS_Float bf)

void	setBScaling (EGS_Input *)

EGS_Float	getBScaling (int ireg) const

virtual void	getLabelRegions (const string &str, vector< int > &regs)

Public Member Functions inherited from EGS_BaseGeometry
	EGS_BaseGeometry (const string &Name)
	Construct a geometry named Name. More...

virtual	~EGS_BaseGeometry ()
	Destructor. More...

bool	isConvex () const
	Is the geometry convex? More...

virtual EGS_Float	howfarToOutside (int ireg, const EGS_Vector &x, const EGS_Vector &u)

virtual EGS_Float	getVolume (int ireg)
	Calculates the volume of region ireg. More...

virtual EGS_Float	getBound (int idir, int ind)
	Returns region boundaries in direction determined by idir. More...

virtual int	getNRegDir (int idir)

int	regions () const
	Returns the number of local regions in this geometry. More...

virtual int	computeIntersections (int ireg, int n, const EGS_Vector &x, const EGS_Vector &u, EGS_GeometryIntersections *isections)
	Calculates intersection distances to region boundaries. More...

void	setMedium (const string &Name)
	Set all regions to a medium with name Name. More...

void	setMedium (int start, int end, const string &Name, int delta=1)
	Set every delta'th region between start and end to the medium named Name. More...

void	setMedium (int imed)
	Set all regions to a medium with index imed. More...

void	setMedium (int istart, int iend, int imed, int delta=1)
	Set every delta'th region between start and end (inclusive) to imed. More...

void	setMedia (EGS_Input *inp)
	Set the media in the geometry from the input pointed to by inp. More...

bool	hasRhoScaling () const
	Does this geometry object have a mass density scaling feature? More...

EGS_Float	getMediumRho (int ind) const

virtual void	setApplication (EGS_Application *app)

bool	hasBScaling () const
	Does this geometry object have a B field scaling feature?

const string &	getName () const
	Get the name of this geometry. More...

void	setDebug (bool deb)
	Turn debugging on. More...

void	setName (EGS_Input *inp)
	Set the name of the geometry from the input inp. More...

void	setBoundaryTolerance (EGS_Input *inp)
	Set the value of the boundary tolerance from the input inp. More...

void	setBoundaryTolerance (EGS_Float tol)
	Set the value of the boundary tolerance from argument.

virtual void	printInfo () const
	Print information about this geometry. More...

int	ref ()
	Increase the reference count to this geometry. More...

int	deref ()
	Decrease the reference count to this geometry. More...

EGS_Float	getBoundaryTolerance ()
	Get the value of the boundary tolerance.

virtual void	getNumberRegions (const string &str, vector< int > &regs)
	Get a list of all the regions labeled with a number.

virtual const string &	getLabelName (const int i)
	Get the name of the i-th explicit label in the geometry.

virtual int	getLabelCount ()
	Get the number of explicit labels in the geometry.

int	setLabels (EGS_Input *input)
	Set the labels from an input block.

int	setLabels (const string &inp)
	Set the labels from an input string.

Protected Member Functions
void	setMedia (EGS_Input inp, int, const int )

Protected Attributes
EGS_BaseGeometry *	bg

EGS_BaseGeometry **	g

int	nbase

int	nmax

bool	new_indexing

int *	reg_to_base

int *	local_start

Protected Attributes inherited from EGS_BaseGeometry
int	nreg
	Number of local regions in this geometry. More...

string	name
	Name of this geometry. More...

short *	region_media
	Array of media indeces. More...

int	med
	Medium index. More...

bool	has_rho_scaling
	Does this geometry have relative mass density scvaling? More...

EGS_Float *	rhor
	Array with relative mass densities. More...

bool	has_B_scaling
	Does this geometry has B field scaling factor? More...

bool	has_Ref_rho

EGS_Float *	bfactor
	Array with B field scaling factors. More...

EGS_Float	rhoRef
	Reference density for B field scaling. More...

int	nref
	Number of references to this geometry. More...

bool	debug
	Debugging flag. More...

bool	is_convex
	Is this geometry convex? More...

EGS_BPType	bproperty
	A bit mask of boolean properties for the entire geometry. More...

EGS_BPType *	bp_array
	An array of boolean properties on a region by region basis. More...

EGS_Float	boundaryTolerance
	Boundary tolerance for geometries that need it.

EGS_Float	halfBoundaryTolerance

vector< label >	labels
	Labels. More...

EGS_Application *	app
	The application this object belongs to.

Static Protected Attributes
static string	type = "EGS_CDGeometry"

Static Protected Attributes inherited from EGS_BaseGeometry
static int	error_flag = 0
	Set to non-zero status if a geometry problem is encountered.

Additional Inherited Members
Static Public Member Functions inherited from EGS_BaseGeometry
static int	findRegion (EGS_Float xp, int np, const EGS_Float *p)
	Find the bin to which xp belongs, given np bin edges p. More...

static int	nMedia ()
	Get the number of media registered so far by all geometries. More...

static const char *	getMediumName (int ind)
	Get the name of medium with index ind. More...

static int	addMedium (const string &medname)
	Add a medium or get the index of an existing medium. More...

static int	getMediumIndex (const string &medname)
	Get the index of a medium named medname. More...

static EGS_BaseGeometry *	createGeometry (EGS_Input *)
	Create a geometry (or geometries) from a given input. More...

static EGS_BaseGeometry *	createSingleGeometry (EGS_Input *inp)
	Create a single geometry from the input inp. More...

static void	clearGeometries ()
	Clears (deletes) all geometries in the currently active geometry list. More...

static EGS_BaseGeometry *	getGeometry (const string &Name)
	Get a pointer to the geometry named Name. More...

static EGS_BaseGeometry **	getGeometries ()

static int	getNGeometries ()

static string	getUniqueName ()
	Get a unique geometry name. More...

static void	describeGeometries ()
	Describes all existing geometries. More...

static void	setActiveGeometryList (int list)
	Set the currently active geometry list. More...

static int	getLastError ()

static void	resetErrorFlag ()

Detailed Description

A "combinatorial dimension" geometry.

The name of this geometry type is not very intuitive but resulted from an early, much less general implementation, which was called a "combinatorial dimension" (CD) geometry. For a lack of a better name, the CD notation was kept. A CD geometry consists of a base geometry $G_B$ , which defines $n_B$ regions. For each of the $n_B$ regions there are geometries $G_0, G_1, ..., G_{n_B-1}$ , which divide the $n_B$ regions into additional regions. As an example, consider a set of 4 parallel planes that defines 3 regions. In region 0 there is a set of 2 spheres, in region 1 a set of 2 cylinders and in region 2 another set of 2 spheres to define a cylindrical structure with rounded ends as shown in the following figure

An example of a CD geometry.

As another example consider a set of 2 cylinders defining 2 regions. In region 0 (within the inner cylinder) there is a set of $N$

parallel planes that define $N-1$

regions and in region 1 of the base cylinder there is a set of just 2 planes that defines a single region, as shown in the following figure

An example of a CD geometry.

One could use the second geometry to calculate the depth dose curve of a beam incident from the top, for instance. The CD geometry type is very versatile and can be used to model a wide range of geometrical structures. It is therefore important to understand the logic behind the various geometry methods, which is as follows:

A point is inside a CD geometry if it is inside and in addition it is inside the geometry for the region of in which the point is, if there is such a geometry defined (note: it is possible that a region of the CD geometry does not have an additional geometry defined).
If a point is in region of and in region of (the geometry belonging to region of ), the region index in the CD geometry is $j n_{\rm max} + i$ , where $n_{\rm max}$ is the maximum number of regions for each of the $G_0, G_1, ..., G_{n_B-1}$ .
If the particle is inside a CD geometry in region , then the distance to a boundary is the minimum of the distances to a boundary in and . If the particle first crosses a boundary in , the new region on the other side of the boundary is either $j n_{\rm max} + i'$ , if the new region is still inside of , or -1 if the particle exits . If the particle first crosses a boundary in into a region , then the new region is either $j' n_{\rm max} + i'$ , if the new position is in region inside of $G_{j'}$ , or -1, if the new position is outside of $G_{j'}$
If a particle is outside of a CD geometry, then the distance to a boundary is calculated by following the trajectory until it either enters a region of that is already inside of or enters a geometry in one of the regions of .
When a particle is inside of a CD geometry in region , then $t_\perp$ is given by the minimum of $t_\perp$ from and from
When a particle is outside of a CD geometry, then $t_\perp$ is given by the $t_\perp$ of , if the position is outside of , or by the minimum of the perpendicular distances to and , if the particle is inside of region in (but is obviously outside of ).

Note that in many cases geometry objects that can be modeled as CD geometries could also be modeled as unions with appropriately assigned priorities (see EGS_UnionGeometry). However, due to the fact that in the CD geometries only checks against a single geometry in addition to $G_B$ are required, it is likely that a CD model will be much more efficient than a union model. For instance, the geometry shown in the first figure can be modeled as the union of two sets of spheres and an N-dimensional geometry made from a set of two cylinders and a set of two planes for the middle portion by giving the N-dimensional geometry a higher priority than the sets of spheres.

A CD geometry is defined in the input file using the following key-pair values

library = egs_cdgeometry
base geometry = name of a previously defined geometry
set geometry = region1,  name of a previously defined geometry
set geometry = region2,  name of a previously defined geometry
...

If the same geometry divides several consecutive regions, one can use

set geometry = start region, stop region, name of a previously defined geometry

There can be an arbitrary number of set geometry keys.

As concluding remark for the CD geometry type, it is worth noting that the treatment head of a medical linear accelerator can be efficiently modeled with the help of a CD geometry. This can be seen in the photon_linac.geom example geometry file. Many of the other examples also employ a CD-geometry.

A simple example:

:start geometry definition:

    # The base geometry, this will be the Chopping Device (CD)
    # The base geometry can be any geometry, even a composite one
    :start geometry:
        name        = my_cd_planes
        library     = egs_planes
        type        = EGS_Zplanes
        positions   = -3 3 5
        # No media required
    :stop geometry:

    :start geometry:
        name        = my_cd_cylinder
        library     = egs_cylinders
        type        = EGS_ZCylinders
        radii       = 1.6 2
        :start media input:
            media = air water
            set medium = 1 1
        :stop media input:
    :stop geometry:

    :start geometry:
        name        = my_cd_sphere
        library     = egs_spheres
        midpoint = 0 0 3
        radii = 1.6 2
        :start media input:
            media = air water
            set medium = 1 1
        :stop media input:
    :stop geometry:

    # The composite geometry
    :start geometry:
        name            = my_cd
        library         = egs_cdgeometry
        base geometry   = my_cd_planes
        # set geometry = 1 geom means:
        # "in region 1 of the basegeometry, use geometry "geom"
        set geometry   = 0 my_cd_cylinder
        set geometry   = 1 my_cd_sphere
        # The final region numbers are attributed by the cd geometry object;
        # Use the viewer to determine region numbers
    :stop geometry:

    simulation geometry = my_cd

:stop geometry definition:

A simple example with clipping plane 1,0,0,0

Definition at line 263 of file egs_cd_geometry.h.

Member Data Documentation

bool EGS_CDGeometry::new_indexing

protected

If true, use new indexing style

Definition at line 892 of file egs_cd_geometry.h.

int* EGS_CDGeometry::reg_to_base

protected

If new indexing style is used, converts global region to base region

Definition at line 895 of file egs_cd_geometry.h.

int* EGS_CDGeometry::local_start

protected

If new indexing style is used, local_start[ibase] is the first region in base region ibase

Definition at line 898 of file egs_cd_geometry.h.

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

/home/rwtownson/EGSnrc/HEN_HOUSE/egs++/geometry/egs_cd_geometry/egs_cd_geometry.h
/home/rwtownson/EGSnrc/HEN_HOUSE/egs++/geometry/egs_cd_geometry/egs_cd_geometry.cpp

Public Member Functions

Protected Member Functions

Protected Attributes

Static Protected Attributes

Additional Inherited Members

Detailed Description

Member Data Documentation