Class InitializationMethod

Base class for algorithms that initialize a particle system. Inherit from this class and implement a method called Generate to create an initialization algorithm.

An initialization algorithm creates a system of InitializationParticles, which is used as a template to initialize the system of Particles in which the simulation is carried out.

Inheritance

object

InitializationMethod

BinOpTestInitializer

ChiralityAndCompassInitializer

CollisionTestAlgoInitializer

CollisionTestAlgo2Initializer

ExpandedCircuitTestInitializer

JMTestInitializer

LeaderElectionInitializer

LineFormationInitializer

ObjectTestInitializer

PASCTestAlgoInitializer

SingleSourceSPInitializer

SmartMaterialInitializer

SubroutineTestInitializer

SubroutineTest2Initializer

InitRandomWithHoles

Namespace: AS2

Assembly: .dll

Syntax

public abstract class InitializationMethod

Constructors

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InitializationMethod(ParticleSystem)

Declaration

public InitializationMethod(ParticleSystem system)

Parameters

Type	Name	Description
ParticleSystem	system

Fields

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system

The system in which particles are created.

Declaration

private ParticleSystem system

Field Value

Type	Description
ParticleSystem

Methods

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AddObjectToSystem(ParticleObject)

Adds a copy of the given object o to the system. Note that you cannot make any changes to an object once it has been added to the system.

Declaration

public void AddObjectToSystem(ParticleObject o)

Parameters

Type	Name	Description
ParticleObject	o	The object to be added.

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AddParticle(Vector2Int, Direction, Chirality, Compass)

Adds a new particle with the given parameters to the system.

Declaration

public InitializationParticle AddParticle(Vector2Int position, Direction headDir = Direction.NONE, Initialization.Chirality chirality = Chirality.CounterClockwise, Initialization.Compass compassDir = Compass.E)

Parameters

Type	Name	Description
Vector2Int	position	The initial tail position of the particle.
Direction	headDir	The initial global head direction of the particle. NONE means that the particle is contracted.
Initialization.Chirality	chirality	The chirality of the particle.
Initialization.Compass	compassDir	The compass direction of the particle.

Returns

Type	Description
InitializationParticle	The new initialization particle.

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CreateObject(Vector2Int, int)

Creates a new object occupying the given position. When the object is finished, submit it to the system by calling AddObjectToSystem(ParticleObject).

Declaration

public ParticleObject CreateObject(Vector2Int pos, int identifier = 0)

Parameters

Type	Name	Description
Vector2Int	pos	The first grid position occupied by the new object.
int	identifier	The identifier of the new object. Does not have to be unique.

Returns

Type	Description
ParticleObject	A new object with the given `identifier` occupying the given position `pos`.

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GenerateRandomConnectedPositions(Vector2Int, int, float, bool, Func<Vector2Int, bool>, bool, bool, float)

Randomly generates a set of connected grid positions according to the given constraints.

The algorithm performs a breadth-first search starting at the given startPos. In each iteration, one of the open neighbors is chosen randomly to place a position or mark a position as a hole. If there are no more open neighbor positions, one of the marked hole positions is chosen instead. Before placing a new position, it is checked whether doing this would close an inner boundary in case this is not allowed.

Declaration

public List<Vector2Int> GenerateRandomConnectedPositions(Vector2Int startPos, int numPositions, float holeProb = 0.3, bool fillHoles = false, Func<Vector2Int, bool> excludeFunc = null, bool allowExcludedHoles = true, bool prioritizeInner = false, float lambda = 0.1)

Parameters

Type	Name	Description
Vector2Int	startPos	The start position of the shape. This position is always part of the resulting set, even if it should be excluded.
int	numPositions	The desired number of grid positions in the generated set.
float	holeProb	The probability of a random candidate position selected to be kept unoccupied.
bool	fillHoles	If `true`, the system of positions is not allowed to have inner boundaries.
Func<Vector2Int, bool>	excludeFunc	A function that marks grid positions as excluded such that no excluded position is contained in the resulting set. Note that it is possible that the resulting set is smaller than desired if there is not enough room for all positions.
bool	allowExcludedHoles	If `fillHoles` is `true`, this controls whether inner boundaries that surround empty regions containing excluded positions are allowed.
bool	prioritizeInner	If `true`, new positions are not selected uniformly at random from the set of candidate locations, but using an exponential distribution that prioritizes positions close to the `startPos`.
float	lambda	The lambda parameter of the exponential distribution if `prioritizeInner` is `true`. Larger values lead to a stronger bias towards positions close to `startPos`. Very small values can lead to a bias towards positions further away.

Returns

Type	Description
List<Vector2Int>	A list of grid positions forming a connected system according to the specified constraints.

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GenerateRandomWithHoles(int, float, Chirality, Compass)

Generates a system with a fixed number of particles using a randomized breadth-first-search algorithm that leaves out some positions to insert holes. It is guaranteed that the desired number of particles is placed because if all available locations are marked as holes, one of them is chosen at random to be replaced with a particle and keep the algorithm going. All particles are contracted.

Declaration

public void GenerateRandomWithHoles(int numParticles = 50, float holeProb = 0.3, Initialization.Chirality chirality = Chirality.CounterClockwise, Initialization.Compass compassDir = Compass.E)

Parameters

Type	Name	Description
int	numParticles	The number of particles to place.
float	holeProb	The probability of a grid position becoming a hole when it is first encountered. Note that the final system might still have holes if this is set to `0`.
Initialization.Chirality	chirality	The chirality setting for all particles.
Initialization.Compass	compassDir	The compass setting for all particles.

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GetParticles()

Returns an array of all currently placed particles. This is useful for cases where particle parameters have to be set after the particles were placed and where chirality and compass directions were chosen randomly.

Declaration

public InitializationParticle[] GetParticles()

Returns

Type	Description
InitializationParticle[]	An array containing all current particles.

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HoleValidSearch(Vector2Int, Vector2Int, Vector2Int, HashSet<Vector2Int>, Func<Vector2Int, bool>)

Random placement helper that checks whether a hole that would be closed by placing a new position is allowed or not. Uses a BFS to search for a goal node that is a corner of the occupied system's bounding box or for any excluded position.

Declaration

private bool HoleValidSearch(Vector2Int startNode, Vector2Int goalNode, Vector2Int openingPos, HashSet<Vector2Int> occupied, Func<Vector2Int, bool> excludeFunc)

Parameters

Type	Name	Description
Vector2Int	startNode	The node from which the search should be started.
Vector2Int	goalNode	The closest corner of the occupied system's bounding rectangle. If the search ever visits this position's x or y coordinate, the hole is considered to be open to the outer boundary.
Vector2Int	openingPos	The grid node where the new position should be placed, used to limit the search to this side of the hole.
HashSet<Vector2Int>	occupied	The set of occupied positions.
Func<Vector2Int, bool>	excludeFunc	The function that marks positions as excluded. Must not be `null`.

Returns

Type	Description
bool	`true` if and only if the search reaches the bounding rectangle of the occupied system or an excluded node.

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IsPositionHoleOpening(Vector2Int, HashSet<Vector2Int>, Func<Vector2Int, bool>, bool)

Random placement helper that checks whether placing a position would close an inner boundary that should not be closed.

Declaration

private bool IsPositionHoleOpening(Vector2Int pos, HashSet<Vector2Int> occupied, Func<Vector2Int, bool> excludeFunc, bool allowExcludedHoles)

Parameters

Type	Name	Description
Vector2Int	pos	The new position to be placed.
HashSet<Vector2Int>	occupied	The set of already occupied positions.
Func<Vector2Int, bool>	excludeFunc	A function marking some grid nodes as excluded.
bool	allowExcludedHoles	Determines whether inner boundaries around empty regions that contain excluded positions are allowed.

Returns

Type	Description
bool	`true` if and only if placing `pos` would close an inner boundary that should not be closed.

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PlaceParallelogram(Vector2Int, Direction, int, bool, int, Chirality, Compass)

Adds contracted particles in the shape of a parallelogram. The particles are added row by row, where length determines how many particles are in a row and height determines how many rows there are. Rows are offset to form an acute angle at the start location if acuteAngle is true, i.e., the offset direction is the main direction rotated by 60� in counter-clockwise direction. Otherwise, the offset direction will be rotated by 120� and the angle becomes obtuse.

Declaration

public void PlaceParallelogram(Vector2Int startPos, Direction mainDir, int length, bool acuteAngle = true, int height = 1, Initialization.Chirality chirality = Chirality.CounterClockwise, Initialization.Compass compass = Compass.E)

Parameters

Type	Name	Description
Vector2Int	startPos	The position at which the first particle will be placed.
Direction	mainDir	The direction in which rows grow.
int	length	The number of particles in each row.
bool	acuteAngle	If `true`, the parallelogram's angle at the first particle is acute (60�), otherwise, it is obtuse (120�).
int	height	The number of rows.
Initialization.Chirality	chirality	The chirality setting for all particles.
Initialization.Compass	compass	The compass setting for all particles.

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RemoveParticleAt(Vector2Int)

Removes the InitializationParticle at the given position.

Declaration

public void RemoveParticleAt(Vector2Int position)

Parameters

Type	Name	Description
Vector2Int	position	The grid position from which a particle should be removed. If an expanded particle occupies this position, its other occupied position will be free as well.

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TryGetParticleAt(Vector2Int, out InitializationParticle)

Tries to get the InitializationParticle at the given position.

Declaration

public bool TryGetParticleAt(Vector2Int position, out InitializationParticle particle)

Parameters

Type	Name	Description
Vector2Int	position	The grid position at which to look for the particle.
InitializationParticle	particle	The particle at the given position, if it exists, otherwise `null`.

Returns

Type	Description
bool	`true` if and only if a particle was found at the given position.