Class SubComparison

Implements binary comparison for two numbers a, b stored in the same chain.

Determines whether a > b, a < b or a = b and makes the result available to all amoebots on the chain.

This procedure requires at least 2 pins and it always uses the "outermost / leftmost" pins when traversing the chain. If an amoebot occurs on the chain multiple times, its predecessor and successor directions must be different for all occurrences.

Usage:

• Establish a chain of amoebots such that each amoebot knows its predecessor and successor (except the start and end amoebots). Each amoebot should store a bit a and a bit b.
• Initialize using the Init(bool, bool, Direction, Direction) method. You must pass the bits a and b and the two chain directions. The chain start should have no predecessor and the end should have no successor.
• Call SetupPinConfig(PinConfiguration) to modify the pin configuration.
• Call ActivateSend() in the same round to start the procedure.
• After this, call ActivateReceive(), SetupPinConfig(PinConfiguration), and ActivateSend() in this order in every round.
• The procedure can be paused after each ActivateReceive() call and resumed by continuing with SetupPinConfig(PinConfiguration) in some future round.
• Call IsFinished() after ActivateReceive() to check whether the comparison is finished.
• The comparison result is thereafter available through Result() for each amoebot on the chain.

Inheritance

object

Subroutine

SubComparison

Namespace: AS2.Subroutines.BinaryOps

Assembly: .dll

Syntax

public class SubComparison : Subroutine

Constructors

SubComparison(Particle, ParticleAttribute<int>)

Declaration

public SubComparison(Particle p, ParticleAttribute<int> stateAttr = null)

Parameters

Type	Name	Description
Particle	p
ParticleAttribute<int>	stateAttr

Fields

bit_A

Declaration

private const int bit_A = 2

Field Value

Type	Description
int

bit_B

Declaration

private const int bit_B = 3

Field Value

Type	Description
int

bit_Finished

Declaration

private const int bit_Finished = 10

Field Value

Type	Description
int

state

Declaration

private ParticleAttribute<int> state

Field Value

Type	Description
ParticleAttribute<int>

Methods

ActivateReceive()

Activation during ActivateBeep() to receive the beeps sent in the last round. Should always be called before SetupPinConfig(PinConfiguration) and ActivateSend(), except in the very first activation, where it should not be called.

Declaration

public void ActivateReceive()

ActivateSend()

Activation during ActivateBeep() to send the beeps required for this step. Must be called after ActivateReceive() and SetupPinConfig(PinConfiguration).

Declaration

public void ActivateSend()

Bit_A()

This amoebot's bit of a.

Declaration

public bool Bit_A()

Returns

Type	Description
bool	Whether this amoebot's bit of a is equal to 1.

Bit_B()

This amoebot's bit of b.

Declaration

public bool Bit_B()

Returns

Type	Description
bool	Whether this amoebot's bit of b is equal to 1.

GetStateBit(int)

Helper for reading a single bit from the state integer.

Declaration

private bool GetStateBit(int bit)

Parameters

Type	Name	Description
int	bit	The position of the bit.

Returns

Type	Description
bool	The value of the state bit at position bit.

Init(bool, bool, Direction, Direction)

Initializes the subroutine. Must be called by each amoebot on the chain that stores a and b.

Declaration

public void Init(bool a, bool b, Direction predDir, Direction succDir)

Parameters

Type	Name	Description
bool	a	This amoebot's bit of a.
bool	b	This amoebot's bit of b.
Direction	predDir	The direction of the predecessor. Should be NONE only at the start of the chain.
Direction	succDir	The direction of the successor. Should be NONE only at the end of the chain.

IsFinished()

Checks whether the procedure is finished. Should be called after ActivateReceive().

Declaration

public bool IsFinished()

Returns

Type	Description
bool	true if and only if the comparison procedure has finished.

PredDir()

Helper for reading the predecessor direction from the state integer.

Declaration

private Direction PredDir()

Returns

Type	Description
Direction	The direction of the chain predecessor.

Result()

Returns the result of the comparison after the procedure has finished.

Declaration

public SubComparison.ComparisonResult Result()

Returns

Type	Description
SubComparison.ComparisonResult	The result of comparing a to b.

Round()

Helper for reading the round number from the state integer.

Declaration

private int Round()

Returns

Type	Description
int	The current round number.

SetResult(ComparisonResult)

Helper for setting the comparison result.

Declaration

private void SetResult(SubComparison.ComparisonResult result)

Parameters

Type	Name	Description
SubComparison.ComparisonResult	result	The new value of the result.

SetRound(int)

Helper for setting the round counter.

Declaration

private void SetRound(int round)

Parameters

Type	Name	Description
int	round	The new value of the round counter.

SetStateBit(int, bool)

Helper for setting a single bit from the state integer.

Declaration

private void SetStateBit(int bit, bool value)

Parameters

Type	Name	Description
int	bit	The position of the bit.
bool	value	The new value of the bit.

SetupPinConfig(PinConfiguration)

Sets up the required circuits for the next step in the given pin configuration. This must be called after ActivateReceive() and before ActivateSend().

Declaration

public void SetupPinConfig(PinConfiguration pc)

Parameters

Type	Name	Description
PinConfiguration	pc	The pin configuration to set up. Partition set IDs will always equal one of the IDs of the contained pins.

SuccDir()

Helper for reading the successor direction from the state integer.

Declaration

private Direction SuccDir()

Returns

Type	Description
Direction	The direction of the chain successor.