RMGVertexConfinement::SampleableObject Struct Reference

#include <RMGVertexConfinement.hh>

Collaboration diagram for RMGVertexConfinement::SampleableObject:

Public Member Functions
	SampleableObject (const SampleableObject &)=default
	SampleableObject (G4VPhysicalVolume *physvol, G4RotationMatrix rot, G4ThreeVector trans, G4VSolid *solid, bool is_native_sampleable=false, bool on_surface=false)
	SampleableObject constructor.
bool	IsInside (const G4ThreeVector &vertex) const
	Check if the vertex is inside the solid.
bool	Sample (G4ThreeVector &vertex, size_t max_attempts, bool force_containment_check, size_t &n_trials) const
	Generate a sample from the solid.
bool	GenerateSurfacePoint (G4ThreeVector &vertex, size_t max_attempts, size_t max_intersections) const
	Generate a point on the surface of the solid.
std::vector< G4ThreeVector >	GetIntersections (G4ThreeVector start, G4ThreeVector dir) const
	Get the number of intersections between the solid and the line starting at start with direction dir.
void	GetDirection (G4ThreeVector &dir, G4ThreeVector &pos) const
	Get a position and direction for the generic surface sampling algorithm.
void	RecalcMass (int z, int n)

Public Attributes
G4VPhysicalVolume *	physical_volume = nullptr
G4VSolid *	sampling_solid = nullptr
G4RotationMatrix	rotation
G4ThreeVector	translation
double	volume = -1
double	mass = -1
double	surface = -1
bool	surface_sample = false
bool	native_sample = false
size_t	max_num_intersections = 0

Detailed Description

An object which we can generate position samples in. Based on either a G4VPhysicalVolume or geometrical volume defined by a G4VSolid . The sampling can be performed either on the surface or in the volume of the solid.

This structure must contain at least a non-null pointer, between the physical_volume and sampling_solid arguments. The idea is that:

• physical volumes get always a bounding box assigned, but at later time
• purely geometrical volumes only have the sampling_solid member defined

Constructor & Destructor Documentation

SampleableObject()

RMGVertexConfinement::SampleableObject::SampleableObject	(	G4VPhysicalVolume *	physvol,
		G4RotationMatrix	rot,
		G4ThreeVector	trans,
		G4VSolid *	solid,
		bool	is_native_sampleable = false,
		bool	on_surface = false )

SampleableObject constructor.

Parameters

physvol	The physical volume.
rot	A rotation matrix for the sampling solid.
trans	A translation vector for the sampling solid.
solid	A solid for geometrical volume sampling or for generating candidate points or rejection sampling.
is_native_sampleable	A flag of whether the solid is natively sampeable.
on_surface	A flag of whether the solid should be sampled on the surface.

Member Function Documentation

GenerateSurfacePoint()

bool RMGVertexConfinement::SampleableObject::GenerateSurfacePoint ( G4ThreeVector & vertex, size_t max_attempts, size_t max_intersections ) const

nodiscard

Generate a point on the surface of the solid.

This follows the algorithm from https://arxiv.org/abs/0802.2960.

• Produce a direction vector corresponding to a uniform flux in a bounding sphere.
• Find the intersections of this line with the solid.
• Pick one intersection, or repeat.

Parameters

vertex	The sampled vertex,
max_attempts	The maximum number of attempts to find a valid vertex.
max_intersections	The maximum number of intersections possible for the solid, can be an overestimate.

GetDirection()

void RMGVertexConfinement::SampleableObject::GetDirection	(	G4ThreeVector &	dir,
		G4ThreeVector &	pos ) const

Get a position and direction for the generic surface sampling algorithm.

This generates a point on a bounding sphere, then shifts by some impact parameter, following the algorithm from https://arxiv.org/abs/0802.2960. This produces a uniform and isotropic flux inside the bounding sphere.

Parameters

dir	The direction vector for the point.
pos	The initial position for the point.

GetIntersections()

std::vector< G4ThreeVector > RMGVertexConfinement::SampleableObject::GetIntersections ( G4ThreeVector start, G4ThreeVector dir ) const

nodiscard

Get the number of intersections between the solid and the line starting at start with direction dir.

This is used in the generic surface sampling algorithm. This function makes use of the methods GetDistanceToIn(p,v) and GetDistanceToOut(p,v) of G4VSolid . It continually looks for the distance to the next boundary (along the line) until this becomes zero indicating there are no more intersections.

Parameters

start	The starting vector of the line, note this should be outside the solid.
dir	The direction vector.

Returns

A vector of the points of intersection.

IsInside()

bool RMGVertexConfinement::SampleableObject::IsInside ( const G4ThreeVector & vertex ) const

nodiscard

Check if the vertex is inside the solid.

Parameters

vertex

The sampled vertex.

Returns

Boolean flag of whether the vertexx is inside the solid.

Sample()

bool RMGVertexConfinement::SampleableObject::Sample ( G4ThreeVector & vertex, size_t max_attempts, bool force_containment_check, size_t & n_trials ) const

nodiscard

Generate a sample from the solid.

Depending on if the solid is a basic one either sample natively, or using rejection sampling. Either samples the volume or the surface depending on the surface_sample member.

• For surface sampling mode the solid is either natively sampled (if this is implemented), or is sampled with SampleableObject::GenerateSurfacePoint
• For volume sampling, if the solid is not natively sampleable, points are generated in a bounding box and then rejection sampling is used using SampleableObject::IsInside.

Parameters

vertex	The sampled vertex.
max_attempts	The maximum number of candidate vertices for rejection sampling.
force_containment_check	Whether to force a check on where the point is inside the solid.
n_trials	The total number of trials performed.

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

• /home/docs/checkouts/readthedocs.org/user_builds/remage/checkouts/latest/include/RMGVertexConfinement.hh
• /home/docs/checkouts/readthedocs.org/user_builds/remage/checkouts/latest/src/RMGVertexConfinement.cc