Class HelicityGenerator

java.lang.Object

org.jlab.detector.helicity.HelicityGenerator

All Implemented Interfaces:

Comparable<HelicityGenerator>, Comparator<HelicityGenerator>

public final class HelicityGenerator
extends Object
implements Comparable<HelicityGenerator>, Comparator<HelicityGenerator>

Helicity Pseudo-Random Sequence. This calculates the first helicity state in each pattern (quartet/octet/toggle), according to the specs here: https://hallaweb.jlab.org/equipment/daq/HelicityUsersGuideFeb4.pdf Note, the convention above, and internally in this class, is HIGH=0=+ and LOW=1=-. Note, this pseudorandom generator operates on raw helicity, and does not produce the same sequence if you just reverse all the states, so the HWP-corrected helicity cannot be used here. User calls addState() until initialized()==true, then getState(). Public interface requires HelicityBit (not integers).

Author:

baltzell

Field Summary

Fields

Modifier and Type	Field	Description
static final int	REGISTER_SIZE

Constructor Summary

Constructors

Constructor	Description
HelicityGenerator()

Method Summary

Modifier and Type	Method	Description
void	addState(HelicityBit bit)	Let the user add a state to initialize the sequence.
void	addState(HelicityState state)	Let the user add a state to initialize the sequence.
int	compare(HelicityGenerator o1, HelicityGenerator o2)
int	compareTo(HelicityGenerator other)
HelicityBit	get(int n)	Get the nth state in the sequence.
int	getOffset()
long	getTimestamp()	Get the timestamp of the first state in the generator sequence.
final boolean	initialize(List<HelicityState> states)	Initialize with a list of states.
boolean	initialized()	Test whether the generator is sufficiently initialized such that get(int) method can be called, based on whether the number of added states is at least REGISTER_SIZE.
void	reset()	Reset the generator, clearing all added states, in order to reuse this HelicityGenerator for a new sequence.
void	setClock(double clock)
int	size()	Get the number of states currently in the generator's sequence.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface java.util.Comparator

equals, reversed, thenComparing, thenComparing, thenComparing, thenComparingDouble, thenComparingInt, thenComparingLong

Field Details

REGISTER_SIZE

public static final int REGISTER_SIZE

See Also:

• Constant Field Values

Constructor Details

HelicityGenerator

public HelicityGenerator()

Method Details

setClock

public void setClock(double clock)

compareTo

public int compareTo(HelicityGenerator other)

Specified by:

compareTo in interface Comparable<HelicityGenerator>

compare

public int compare(HelicityGenerator o1,
 HelicityGenerator o2)

Specified by:

compare in interface Comparator<HelicityGenerator>

getTimestamp

public long getTimestamp()

Get the timestamp of the first state in the generator sequence.

Returns:

timestamp (4ns)

reset

public void reset()

Reset the generator, clearing all added states, in order to reuse this HelicityGenerator for a new sequence.

initialized

public boolean initialized()

Test whether the generator is sufficiently initialized such that get(int) method can be called, based on whether the number of added states is at least REGISTER_SIZE.

Returns:

whether the sequence is initialized

size

public int size()

Get the number of states currently in the generator's sequence.

Returns:

size

addState

public void addState(HelicityBit bit)

Let the user add a state to initialize the sequence. This must be the first helicity state in the next pattern. States must be added serially and without skipped patterns. Requires initialized() is false and a defined HelicityBit, else throws an exception..

Parameters:

bit - the HelicityBit to add to the sequence. This must be the raw helicity, e.g. HelicityState.getHelicityRaw(), not the HWP-corrected version.

addState

public void addState(HelicityState state)

Let the user add a state to initialize the sequence. This just calls addState(HelicityBit) with the raw

invalid reference

#HelicityBit

from the given

invalid reference

#HelicityState

. This must be the first helicity state in the next pattern. States must be added serially and without skipped patterns. Requires initialized() is false and a defined

invalid reference

#HelicityState

.

Parameters:

state - the HelicityState to add to the sequence.

get

public HelicityBit get(int n)

Get the nth state in the sequence. Requires initialized()==true.

Parameters:

n - number of states after the first one.

Returns:

the nth HelicityBit in the sequence.

initialize

public final boolean initialize(List<HelicityState> states)

Initialize with a list of states. The states are first time-ordered, and error-checking is done to find the first valid sequence of sufficient length in the list and use it to initialize the generator, otherwise the return value will be false.

Parameters:

states - list of HelicityState objects

Returns:

success of initializing the generator

getOffset

public int getOffset()