Class Spiral

Implements the Spiral2LineSegment algorithm. See https://doi.org/10.4230/LIPIcs.SAND.2026.11.
Reconfigures a spiral structure into a straight line while strictly preserving the sequence order of the amoebots.

The algorithm achieves constant time by first converting the spiral into a y-monotone structure. It constructs a base line, safely disconnects outer segments into independent arms, and aligns them in parallel using shearing operations. The final monotone structure is then straightened using the Monotone2Line algorithm.

Inheritance

object

Suboracle<Spiral>

Spiral

Namespace: AS2.Suboracles.Reconfiguration

Assembly: .dll

Syntax

public class Spiral : Suboracle<Spiral>

Constructors

Spiral(Particle)

Declaration

public Spiral(Particle rep)

Parameters

Type	Name	Description
Particle	rep

Fields

anchor

Declaration

private ParticleAlgorithm anchor

Field Value

Type	Description
ParticleAlgorithm

anchor2

Declaration

private ParticleAlgorithm anchor2

Field Value

Type	Description
ParticleAlgorithm

arm

Declaration

private ParticleAttribute<bool> arm

Field Value

Type	Description
ParticleAttribute<bool>

baseline

Declaration

private ParticleAttribute<bool> baseline

Field Value

Type	Description
ParticleAttribute<bool>

clockwise

Declaration

private bool clockwise

Field Value

Type	Description
bool

directionExtra

Declaration

private ParticleAttribute<Direction> directionExtra

Field Value

Type	Description
ParticleAttribute<Direction>

directionIn

Declaration

private ParticleAttribute<Direction> directionIn

Field Value

Type	Description
ParticleAttribute<Direction>

directionOut

Declaration

private ParticleAttribute<Direction> directionOut

Field Value

Type	Description
ParticleAttribute<Direction>

emptyLeft

Declaration

private ParticleAttribute<int> emptyLeft

Field Value

Type	Description
ParticleAttribute<int>

emptyRight

Declaration

private ParticleAttribute<int> emptyRight

Field Value

Type	Description
ParticleAttribute<int>

hideBonds

Declaration

private List<ParticleAlgorithm> hideBonds

Field Value

Type	Description
List<ParticleAlgorithm>

id

Declaration

private ParticleAttribute<int> id

Field Value

Type	Description
ParticleAttribute<int>

leftBaseline

Declaration

private ParticleAttribute<bool> leftBaseline

Field Value

Type	Description
ParticleAttribute<bool>

leftBaselineMembers

Declaration

private List<ParticleAlgorithm> leftBaselineMembers

Field Value

Type	Description
List<ParticleAlgorithm>

leftCorners

Declaration

private List<Spiral> leftCorners

Field Value

Type	Description
List<Spiral>

monotoneToLineSuboracle

Declaration

private MonotoneToLine monotoneToLineSuboracle

Field Value

Type	Description
MonotoneToLine

parallelogramSuboracle

Declaration

private Parallelogram parallelogramSuboracle

Field Value

Type	Description
Parallelogram

releasedBonds

Declaration

private List<(ParticleAlgorithm, Direction, bool)> releasedBonds

Field Value

Type	Description
List<(ParticleAlgorithm, Direction, bool)>

releasedBonds2

Declaration

private List<(ParticleAlgorithm, Direction, bool)> releasedBonds2

Field Value

Type	Description
List<(ParticleAlgorithm, Direction, bool)>

rightBaseline

Declaration

private ParticleAttribute<bool> rightBaseline

Field Value

Type	Description
ParticleAttribute<bool>

rightBaselineMembers

Declaration

private List<ParticleAlgorithm> rightBaselineMembers

Field Value

Type	Description
List<ParticleAlgorithm>

rightCorners

Declaration

private List<Spiral> rightCorners

Field Value

Type	Description
List<Spiral>

round

Declaration

private ParticleAttribute<int> round

Field Value

Type	Description
ParticleAttribute<int>

shearSuboracle

Declaration

private Shear shearSuboracle

Field Value

Type	Description
Shear

shearSuboracleAnchors

Declaration

private List<Spiral> shearSuboracleAnchors

Field Value

Type	Description
List<Spiral>

trapezoidSuboracle

Declaration

private Trapezoid trapezoidSuboracle

Field Value

Type	Description
Trapezoid

unrollingOnly

Declaration

private ParticleAttribute<bool> unrollingOnly

Field Value

Type	Description
ParticleAttribute<bool>

unrollingSuboracle

Declaration

private Unrolling unrollingSuboracle

Field Value

Type	Description
Unrolling

xDir

Declaration

private Direction xDir

Field Value

Type	Description
Direction

yDir

Declaration

private Direction yDir

Field Value

Type	Description
Direction

zDir

Declaration

private Direction zDir

Field Value

Type	Description
Direction

Methods

GetBorderColor(Direction, Spiral)

Returns the color for the border in the given direction of an amoebot. Used for visualization. If the monotone-to-line suboracle is active, delegates to it. Otherwise, the color represents the spiral bonds: the border is blue for the incoming direction, red for the outgoing direction, green for additional bonds created during the transformation.

Declaration

public Color GetBorderColor(Direction dir, Spiral mv)

Parameters

Type	Name	Description
Direction	dir	The direction for which the color is requested.
Spiral	mv	The suboracle instance of the amoebot.

Returns

Type	Description
Color	Blue for directionIn, red for directionOut, green for directionExtra, transparent otherwise.

Init(List<Spiral>, ParticleAlgorithm, Direction, bool)

Initializes the suboracle for a new run. Assigns IDs to all member particles in the spiral direction with 0 in the center, sets their directionIn and directionOut attributes and determines the coordinate axes. Also checks whether extra unrolling is needed for the last x-segment to allow subsequent parallelogram moves. Fallback to only unrolling if there are less than 5 segments.

Declaration

public void Init(List<Spiral> memberParticles, ParticleAlgorithm outer, Direction startDir, bool clockwise)

Parameters

Type	Name	Description
List<Spiral>	memberParticles	The particles that are part of this suboracle instance.
ParticleAlgorithm	outer	The outermost particle of the spiral.
Direction	startDir	The starting direction from the outermost particle towards the center.
bool	clockwise	Whether the spiral turns clockwise.

OnActivate()

Execute the next round of the Spiral algorithm. The method returns true when the structure has been reconfigured into a line. True if the reconfiguration is complete, false otherwise.

Declaration

protected override bool OnActivate()

Returns

Type	Description
bool

Overrides

Suboracle<Spiral>.OnActivate()

RemoveBonds()

Removes all bonds from the particles in the hideBonds list, except for the bonds in the directionIn, directionOut, and directionExtra of each particle. Also handles a few special cases.

Declaration

private void RemoveBonds()