Acts::NullBField Class Reference

Null bfield which returns 0 always. More...

#include <Acts/MagneticField/NullBField.hpp>

Inheritance diagram for Acts::NullBField:

Collaboration diagram for Acts::NullBField:

Classes
struct	Cache
	Cache object for the null magnetic field provider. More...

Public Member Functions
	NullBField ()=default
	Default constructor.
Result< Vector3 >	getField (const Vector3 &position, MagneticFieldProvider::Cache &cache) const override
	Retrieve magnetic field value at a given location.
Result< FieldAndGradient >	getFieldAndGradient (const Vector3 &position, MagneticFieldProvider::Cache &cache) const override
	Retrieve the magnetic field and its spatial gradient at a given location.
bool	isInside (const Vector3 &) const
	check whether given 3D position is inside look-up domain
Acts::MagneticFieldProvider::Cache	makeCache (const Acts::MagneticFieldContext &mctx) const override
	Make an opaque cache for the magnetic field.
bool	providesFieldGradient () const override
	Check if getFieldAndGradient is implemented by this provider.

Additional Inherited Members
Public Types inherited from Acts::MagneticFieldProvider
using	Cache = Acts::AnyBase<sizeof(char) * 512>
	Opaque cache type that can store arbitrary implementation specific cache data.

Detailed Description

Null bfield which returns 0 always.

Member Function Documentation

getField()

Result< Vector3 > Acts::NullBField::getField ( const Vector3 & position, MagneticFieldProvider::Cache & cache ) const

overridevirtual

Retrieve magnetic field value at a given location.

Requires an instance of Acts::MagneticFieldProvider::Cache created through makeCache.

Parameters

[in]	position	global 3D position for the lookup
[in,out]	cache	Field provider specific cache object

Returns

magnetic field vector at given position

Note

The position is ignored and only kept as argument to provide a consistent interface with other magnetic field services.

Implements Acts::MagneticFieldProvider.

getFieldAndGradient()

Result< FieldAndGradient > Acts::NullBField::getFieldAndGradient ( const Vector3 & position, MagneticFieldProvider::Cache & cache ) const

overridevirtual

Retrieve the magnetic field and its spatial gradient at a given location.

Parameters

[in]	position	global 3D position for the lookup
[in,out]	cache	Field provider specific cache object

Returns

field and gradient at the given position, or MagneticFieldError::NotImplemented if providesFieldGradient is false

Note

The field and its gradient are zero.

Reimplemented from Acts::MagneticFieldProvider.

isInside()

bool Acts::NullBField::isInside

(

const Vector3 &

)

const

check whether given 3D position is inside look-up domain

Returns

true if position is inside the defined look-up grid, otherwise false

Note

The method will always return true for the null B-Field

makeCache()

Acts::MagneticFieldProvider::Cache Acts::NullBField::makeCache ( const Acts::MagneticFieldContext & mctx ) const

overridevirtual

Make an opaque cache for the magnetic field.

Instructs the specific implementation to generate a Acts::MagneticFieldProvider::Cache instance for magnetic field lookup.

Parameters

mctx	The magnetic field context to generate cache for

Returns

Cache The opaque cache object

Implements Acts::MagneticFieldProvider.

providesFieldGradient()

bool Acts::NullBField::providesFieldGradient ( ) const

overridevirtual

Check if getFieldAndGradient is implemented by this provider.

If it is false, the caller has to compute the gradient in a different way, for example with finite differences of getField.

Returns

true if the provider implements the field gradient

Reimplemented from Acts::MagneticFieldProvider.