Class MagicSquaresRule

Enforces a rule that certain regions in a puzzle must be magic squares, i.e. the sums of the values in each of their rows, columns, and (optionally) their diagonals add up to the same value.

Note that this does not enforce uniqueness of values within the magic square as a whole. It does, however, prevent value duplication within each row, column, and/or diagonal. This can be combined with other rules if you need proper row, column, box, and/or diagonal uniqueness.

Inheritance

System.Object

MagicSquaresRule

Implements

IRule

Inherited Members

System.Object.Equals(System.Object)

System.Object.Equals(System.Object, System.Object)

System.Object.GetHashCode()

System.Object.GetType()

System.Object.MemberwiseClone()

System.Object.ReferenceEquals(System.Object, System.Object)

System.Object.ToString()

Namespace: SudokuSpice.RuleBased.Rules

Assembly: SudokuSpice.dll

Syntax

public class MagicSquaresRule : IRule

Constructors

MagicSquaresRule(Int32, IEnumerable<Box>, Boolean)

Constructs a rule that will enforce that the given squares are magic squares based on the rows, columns, and, optionally, the diagonals.

Unlike other rules, this rule can only be constructed for a specific puzzle size. Attempting to initialize this rule with an incompatible puzzle will fail.

Declaration

public MagicSquaresRule(int size, IEnumerable<Box> squares, bool includeDiagonals)

Parameters

Type	Name	Description
System.Int32	size	The size of the puzzle this rule applies to.
System.Collections.Generic.IEnumerable<Box>	squares	The locations of the magic squares. The squares' size must be the square root of the puzzle size.
System.Boolean	includeDiagonals	If true, values along the diagonals of the square must also sum to the magic number.

Exceptions

Type	Condition
System.ArgumentException	If the any of the given squares' sizes are not compatible with the given puzzle's size.

Methods

CopyWithNewReference(IReadOnlyPuzzle)

Creates a deep copy of this IRule, with any internal IReadOnlyPuzzle references updated to the given puzzle.

Declaration

public IRule CopyWithNewReference(IReadOnlyPuzzle puzzle)

Parameters

Type	Name	Description
IReadOnlyPuzzle	puzzle	The new puzzle reference to use. To ensure this rule's internal state is correct, this puzzle should contain the same data as the current puzzle referenced by this rule.

Returns

Type	Description
IRule

GetPossibleValues(Coordinate)

Gets the possible values for the given coordinate based on this rule.

Declaration

public BitVector GetPossibleValues(in Coordinate c)

Parameters

Type	Name	Description
Coordinate	c

Returns

Type	Description
BitVector	The possible values represented as a BitVector.

Remarks

When implementing this method, avoid depending on dynamic information in the current puzzle being solved, such as the currently set values. This method must return information that reflects the most recent calls to Update(Coordinate, Int32, CoordinateTracker) or Revert(Coordinate, Int32, CoordinateTracker), as it can be called before or after modifying the underlying puzzle's data.

Revert(Coordinate, Int32)

Undoes an update for the given value at the specified coordinate.

This performs the same internal updates as Revert(Coordinate, Int32, CoordinateTracker), but without passing affected coordinates back to the caller. Therefore this is more efficient in cases where the caller already knows all the possible coordinates that could be affected.

Declaration

public void Revert(in Coordinate c, int val)

Parameters

Type	Name	Description
Coordinate	c	The coordinate where a value is being unset.
System.Int32	val	The value being unset.

Remarks

This method will always be called before reverting the value on the underlying puzzle.

Revert(Coordinate, Int32, CoordinateTracker)

Undoes an update for the given value at the specified coordinate. Tracks affected coordinates in the given tracker.

Declaration

public void Revert(in Coordinate c, int val, CoordinateTracker coordTracker)

Parameters

Type	Name	Description
Coordinate	c	The coordinate where a value is being unset.
System.Int32	val	The value being unset.
CoordinateTracker	coordTracker	The coordinates of unset squares impacted by this change will be tracked in this tracker.

Remarks

This method will always be called before reverting the value on the underlying puzzle.

TryInit(IReadOnlyPuzzle, BitVector)

Tries to initialize this rule to prepare to solve the given puzzle.

Declaration

public bool TryInit(IReadOnlyPuzzle puzzle, BitVector uniquePossibleValues)

Parameters

Type	Name	Description
IReadOnlyPuzzle	puzzle	The puzzle to be solved.
BitVector	uniquePossibleValues	All the unique possible values for this puzzle.

Returns

Type	Description
System.Boolean	False if the puzzle violates this rule and initialization fails, else true.

Remarks

In general, it doesn't make sense to want to maintain the previous state if this method fails. Therefore, it is not guaranteed that the rule's state is unchanged on failure.

Update(Coordinate, Int32, CoordinateTracker)

Updates possible values based on setting the given coordinate to the given value. Tracks affected coordinates in the given tracker.

Declaration

public void Update(in Coordinate c, int val, CoordinateTracker coordTracker)

Parameters

Type	Name	Description
Coordinate	c	The coordinate to update.
System.Int32	val	The value to set c to.
CoordinateTracker	coordTracker	The coordinates of unset squares impacted by this change will be tracked in this tracker.

Remarks

This method will always be called before setting the value on the underlying puzzle.

Implements

IRule