{-# LANGUAGE CPP #-}
{-
Copyright (C) 2018 Dr. Alistair Ward
This file is part of BishBosh.
BishBosh is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
BishBosh is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with BishBosh. If not, see .
-}
{- |
[@AUTHOR@] Dr. Alistair Ward
[@DESCRIPTION@]
* Defines suitable concrete types with which to specialise type-parameters.
* CAVEAT: use of the narrow set of numeric types, results in marginally slower performance without any reduction in space-requirements.
-}
module BishBosh.Types(
-- * Types
-- ** Type-synonyms
CriterionWeight,
CriterionValue,
WeightedMean,
X,
Y,
Distance,
RankValue,
PieceSquareValue,
PositionHash,
RadiusSquared
) where
import qualified Data.Word
#ifdef USE_NARROW_NUMBERS
import qualified Data.Int
#endif
-- | The preferred type by which to weight criteria.
type CriterionWeight =
#ifdef USE_NARROW_NUMBERS
Float
#else
Double -- N.B.: 'Rational' is more accurate, but slower alternative.
#endif
-- | The preferred type by which to value criteria.
type CriterionValue = CriterionWeight
-- | The preferred type by which to represent fitness.
type WeightedMean = CriterionValue
-- | The preferred type by which to represent the abscissa. CAVEAT: while conceptually unsigned, various unguarded calls to 'pred' prevent this.
type X =
#ifdef USE_NARROW_NUMBERS
Data.Int.Int8
#else
Int
#endif
-- | The preferred type by which to represent the ordinate.
type Y = X -- N.B.: it can be independent of 'X'.
{- |
* The preferred type by which to represent the signed distance of a move.
* N.B.: since /distance/ is used to represent only the horizontal or vertical component of a move, rather than a diagonal length, it can be represented by an integral value.
-}
type Distance = X -- N.B.: conceptually independent of both 'X' & 'Y' which could be unsigned.
-- | The preferred type by which to represent the value of a /rank/.
type RankValue = CriterionValue
{- |
* The preferred type by which to represent a /piece-square/ value.
* CAVEAT: performance of 'BishBosh.Evaluation.Fitness.interpolatePieceSquareValues' suffers from use of 'Rational'.
-}
type PieceSquareValue = CriterionValue
-- | The type of the hash used to uniquely represent a /position/.
type PositionHash =
#ifdef USE_NARROW_NUMBERS
Data.Word.Word32 -- CAVEAT: hash-collisions become almost inevitable after @ sqrt bits @ trials.
#else
Data.Word.Word
#endif
{- |
* The preferred type by which to represent the square of the radius of a coordinate, from the centre of the board.
* N.B. for efficiency, @ radius ^ 2 @ is measured, to avoid the need to call @sqrt@.
-}
type RadiusSquared =
#ifdef USE_NARROW_NUMBERS
Float
#else
Double
#endif