BishBosh.Search.Transpositions

AUTHOR

Dr. Alistair Ward

DESCRIPTION

• https://chessprogramming.wikispaces.com/Transposition+Table.
• https://en.wikipedia.org/wiki/Transposition_table.
• http://www.chessbin.com/post/Transposition-Table-and-Zobrist-Hashing.
• Valid move-sequences can be recorded against the hash of the position from which they start.

Types

Type-synonyms

type Transformation move positionHash = Transpositions move positionHash -> Transpositions move positionHash

The type of a function which transforms Transpositions.

Data-types

data Transpositions move positionHash

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

Instances

Empty (Transpositions move positionHash)

Methods

empty :: Transpositions move positionHash

EphemeralData (Transpositions move positionHash)

Methods

getSize :: Transpositions move positionHash -> Int

euthanise :: NPlies -> Transpositions move positionHash -> Transpositions move positionHash

Functions

find :: Ord positionHash => positionHash -> Transpositions move positionHash -> Maybe (Value move)

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

Mutators

insert

Arguments

:: (Ord positionHash, Ord weightedMean)

=> FindFitness move weightedMean

-> positionHash

Represents the game from which the sequence of moves starts.

-> Value move

The value to record.

-> Transformation move 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.