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{-# OPTIONS_GHC -Wall #-}
import qualified Numeric.Sundials.ARKode.ODE as ARK
import qualified Numeric.Sundials.CVode.ODE as CV
import Numeric.LinearAlgebra
import Plots as P
import qualified Diagrams.Prelude as D
import Diagrams.Backend.Rasterific
import Control.Lens
import Test.Hspec
lorenz :: Double -> [Double] -> [Double]
lorenz _t u = [ sigma * (y - x)
, x * (rho - z) - y
, x * y - beta * z
]
where
rho = 28.0
sigma = 10.0
beta = 8.0 / 3.0
x = u !! 0
y = u !! 1
z = u !! 2
_lorenzJac :: Double -> Vector Double -> Matrix Double
_lorenzJac _t u = (3><3) [ (-sigma), rho - z, y
, sigma , -1.0 , x
, 0.0 , (-x) , (-beta)
]
where
rho = 28.0
sigma = 10.0
beta = 8.0 / 3.0
x = u ! 0
y = u ! 1
z = u ! 2
brusselator :: Double -> [Double] -> [Double]
brusselator _t x = [ a - (w + 1) * u + v * u * u
, w * u - v * u * u
, (b - w) / eps - w * u
]
where
a = 1.0
b = 3.5
eps = 5.0e-6
u = x !! 0
v = x !! 1
w = x !! 2
_brussJac :: Double -> Vector Double -> Matrix Double
_brussJac _t x = (3><3) [ (-(w + 1.0)) + 2.0 * u * v, w - 2.0 * u * v, (-w)
, u * u , (-(u * u)) , 0.0
, (-u) , u , (-1.0) / eps - u
]
where
y = toList x
u = y !! 0
v = y !! 1
w = y !! 2
eps = 5.0e-6
stiffish :: Double -> [Double] -> [Double]
stiffish t v = [ lamda * u + 1.0 / (1.0 + t * t) - lamda * atan t ]
where
lamda = -100.0
u = v !! 0
stiffishV :: Double -> Vector Double -> Vector Double
stiffishV t v = fromList [ lamda * u + 1.0 / (1.0 + t * t) - lamda * atan t ]
where
lamda = -100.0
u = v ! 0
_stiffJac :: Double -> Vector Double -> Matrix Double
_stiffJac _t _v = (1><1) [ lamda ]
where
lamda = -100.0
lSaxis :: [[Double]] -> P.Axis B D.V2 Double
lSaxis xs = P.r2Axis &~ do
let ts = xs!!0
us = xs!!1
vs = xs!!2
ws = xs!!3
P.linePlot' $ zip ts us
P.linePlot' $ zip ts vs
P.linePlot' $ zip ts ws
kSaxis :: [(Double, Double)] -> P.Axis B D.V2 Double
kSaxis xs = P.r2Axis &~ do
P.linePlot' xs
main :: IO ()
main = do
let res1 = ARK.odeSolve brusselator [1.2, 3.1, 3.0] (fromList [0.0, 0.1 .. 10.0])
renderRasterific "diagrams/brusselator.png"
(D.dims2D 500.0 500.0)
(renderAxis $ lSaxis $ [0.0, 0.1 .. 10.0]:(toLists $ tr res1))
let res1a = ARK.odeSolve brusselator [1.2, 3.1, 3.0] (fromList [0.0, 0.1 .. 10.0])
renderRasterific "diagrams/brusselatorA.png"
(D.dims2D 500.0 500.0)
(renderAxis $ lSaxis $ [0.0, 0.1 .. 10.0]:(toLists $ tr res1a))
let res2 = ARK.odeSolve stiffish [0.0] (fromList [0.0, 0.1 .. 10.0])
renderRasterific "diagrams/stiffish.png"
(D.dims2D 500.0 500.0)
(renderAxis $ kSaxis $ zip [0.0, 0.1 .. 10.0] (concat $ toLists res2))
let res2a = ARK.odeSolveV (ARK.SDIRK_5_3_4') Nothing 1e-6 1e-10 stiffishV (fromList [0.0]) (fromList [0.0, 0.1 .. 10.0])
let res2b = ARK.odeSolveV (ARK.TRBDF2_3_3_2') Nothing 1e-6 1e-10 stiffishV (fromList [0.0]) (fromList [0.0, 0.1 .. 10.0])
let maxDiff = maximum $ map abs $
zipWith (-) ((toLists $ tr res2a)!!0) ((toLists $ tr res2b)!!0)
hspec $ describe "Compare results" $ do
it "for two different RK methods" $
maxDiff < 1.0e-6
let res2c = CV.odeSolveV (CV.BDF) Nothing 1e-6 1e-10 stiffishV (fromList [0.0]) (fromList [0.0, 0.1 .. 10.0])
putStrLn $ show res2c
let res3 = ARK.odeSolve lorenz [-5.0, -5.0, 1.0] (fromList [0.0, 0.01 .. 10.0])
renderRasterific "diagrams/lorenz.png"
(D.dims2D 500.0 500.0)
(renderAxis $ kSaxis $ zip ((toLists $ tr res3)!!0) ((toLists $ tr res3)!!1))
renderRasterific "diagrams/lorenz1.png"
(D.dims2D 500.0 500.0)
(renderAxis $ kSaxis $ zip ((toLists $ tr res3)!!0) ((toLists $ tr res3)!!2))
renderRasterific "diagrams/lorenz2.png"
(D.dims2D 500.0 500.0)
(renderAxis $ kSaxis $ zip ((toLists $ tr res3)!!1) ((toLists $ tr res3)!!2))
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