{-
	Copyright (C) 2011-2015 Dr. Alistair Ward

	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, see <http://www.gnu.org/licenses/>.
-}
{- |
 [@AUTHOR@]	Dr. Alistair Ward

 [@DESCRIPTION@]	Defines the set of /Spigot/-algorithms which have been implemented.
-}

module Factory.Math.Implementations.Pi.Spigot.Algorithm(
-- * Types
-- ** Data-types
        Algorithm(..)
) where

import qualified        Data.Default
import                  Data.Ratio((%))
import qualified        Factory.Math.Implementations.Pi.Spigot.Gosper           as Math.Implementations.Pi.Spigot.Gosper
import qualified        Factory.Math.Implementations.Pi.Spigot.RabinowitzWagon  as Math.Implementations.Pi.Spigot.RabinowitzWagon
import qualified        Factory.Math.Implementations.Pi.Spigot.Spigot           as Math.Implementations.Pi.Spigot.Spigot
import qualified        Factory.Math.Pi                                         as Math.Pi

-- | Define those /Spigot/-algorithms which have been implemented.
data Algorithm
        = Gosper                -- ^ A /continued fraction/ discovered by /Gosper/.
        | RabinowitzWagon       -- ^ A /continued fraction/ discovered by /Rabinowitz/ and /Wagon/.
        deriving (Eq, Read, Show)

instance Data.Default.Default Algorithm where
        def     = Gosper

instance Math.Pi.Algorithmic Algorithm  where
        openI Gosper                    = Math.Implementations.Pi.Spigot.Spigot.openI Math.Implementations.Pi.Spigot.Gosper.series
        openI RabinowitzWagon           = Math.Implementations.Pi.Spigot.Spigot.openI Math.Implementations.Pi.Spigot.RabinowitzWagon.series

        openR algorithm decimalDigits   = Math.Pi.openI algorithm decimalDigits % (10 ^ pred decimalDigits)