BishBosh.Search.Transpositions

AUTHOR

Dr. Alistair Ward

DESCRIPTION

• https://www.chessprogramming.org/Transposition_Table.
• https://en.wikipedia.org/wiki/Transposition_table.
• Valid qualifiedMove-sequences can be recorded against the hash of the position from which they start.

Types

Type-synonyms

type Transformation qualifiedMove positionHash = Transpositions qualifiedMove positionHash -> Transpositions qualifiedMove positionHash

The type of a function which transforms Transpositions.

Data-types

data Transpositions qualifiedMove positionHash

Stores the result of an alpha-beta search from a position.

Instances

Empty (Transpositions qualifiedMove positionHash)

Defined in BishBosh.Search.Transpositions

Methods

empty :: Transpositions qualifiedMove positionHash

EphemeralData (Transpositions qualifiedMove positionHash)

Defined in BishBosh.Search.Transpositions

Methods

getSize :: Transpositions qualifiedMove positionHash -> Int

euthanise :: NPlies -> Transpositions qualifiedMove positionHash -> Transpositions qualifiedMove positionHash

Functions

find :: Ord positionHash => positionHash -> Transpositions qualifiedMove positionHash -> Maybe (TranspositionValue qualifiedMove)

Returns any value previously recorded when searching from the specified position.

Mutators

insert

Arguments

:: Ord positionHash

=> FindFitness qualifiedMove

-> positionHash

Represents the game from which the sequence of qualifiedMoves starts.

-> TranspositionValue qualifiedMove

The value to record.

-> Transformation qualifiedMove positionHash

• Optionally record a value found while searching for the optimal move from a position, against the position's hash.
• If a matching key already exists, it's replaced if the new value is considered to be better.