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{-# OPTIONS_GHC -Wall #-}
import qualified Data.Vector.Storable as V
import Numeric.Sundials.Arkode.ODE
brusselator :: Double -> V.Vector Double -> V.Vector Double
brusselator _t x = V.fromList [ a - (w + 1) * u + v * u^2
, w * u - v * u^2
, (b - w) / eps - w * u
]
where
a = 1.0
b = 3.5
eps = 5.0e-6
u = x V.! 0
v = x V.! 1
w = x V.! 2
stiffish t v = V.fromList [ lamda * u + 1.0 / (1.0 + t * t) - lamda * atan t ]
where
lamda = -100.0
u = v V.! 0
main :: IO ()
main = do
let res = solveOde brusselator (V.fromList [1.2, 3.1, 3.0]) (V.fromList [0.0, 1.0 .. 10.0])
putStrLn $ show res
let res = solveOde stiffish (V.fromList [1.0]) (V.fromList [0.0, 0.1 .. 10.0])
putStrLn $ show res
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