Parameters.hs

{-
Copyright (C) 2015 Leon Medvinsky

This program 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.

This program 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 this program; if not, write to the Free Software
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
-}

{-|
Module      : Neet.Parameters
Description : Learning parameters
Copyright   : (c) Leon Medvinsky, 2015

License     : GPL-3
Maintainer  : lmedvinsky@hotmail.com
Stability   : experimental
Portability : portable
-}

module Neet.Parameters (Parameters(..), DistParams(..), defParams, defDP, smallParams ) where


-- | The genetic parameters
data Parameters =
  Parameters { mutWeightRate  :: Double -- ^ How often weights are mutated
             , newWeightRate  :: Double -- ^ How often weights are replaced if mutated
             , pertAmount     :: Double -- ^ Max amount of perturbation
             , weightRange    :: Double -- ^ A new max is between negative this and positive this
             , addConnRate    :: Double -- ^ How often new connections are made
             , addNodeRate    :: Double -- ^ How often new nodes are added
             , largeSize      :: Int    -- ^ The minimum size for a species to be considered large
             , disableChance  :: Double -- ^ How likely that a disabled parent results
                                        -- in a disabled child
             , distParams     :: DistParams -- ^ Parameters for the distance function
             , dropTime       :: Maybe Int -- ^ Drop a species if it doesn't improve for this long,
                                           -- and it hasn't hosted the most successful genome.
             , noCrossover    :: Double -- ^ Percent of population that mutates without crossover
             }
  deriving (Show)


data DistParams =
  DistParams { dp1 :: Double -- ^ Coefficient to the number of excess genes
             , dp2 :: Double -- ^ Coefficient to the number of disjoint genes
             , dp3 :: Double -- ^ Coefficient to the average weight differences
             , delta_t :: Double -- ^ How close counts as the same species
             } 
  deriving (Show)


-- | The parameters used in the original NEAT paper, except the perturbation amount
-- and threshold for size.
defParams :: Parameters
defParams =
  Parameters { mutWeightRate = 0.8
             , newWeightRate = 0.1
             , pertAmount = 0.1    -- This value I made up
             , weightRange = 10    -- This one too
             , addConnRate = 0.3
             , addNodeRate = 0.03
             , largeSize = 20
             , disableChance = 0.75
             , distParams = defDP
             , dropTime = Just 15
             , noCrossover = 0.25
             } 


-- | Parameters used in the paper for small populations
smallParams :: Parameters
smallParams = defParams { addConnRate = 0.05 }


-- | Parameters used for distance in the paper
defDP :: DistParams
defDP = DistParams 1 1 0.4 3