1 files changed, 32 insertions, 0 deletions

diff --git a/packages/sundials/src/Main.hs b/packages/sundials/src/Main.hs
index 5e51372..895e610 100644
--- a/packages/sundials/src/Main.hs
+++ b/packages/sundials/src/Main.hs
@@ -11,6 +11,9 @@ import           Diagrams.Backend.Rasterific
 import           Control.Lens
 import           Data.List (zip4)
 
+import           Text.PrettyPrint.HughesPJClass
+import           Data.List (intercalate)
+
 
 brusselator _t x = [ a - (w + 1) * u + v * u^2
                    , w * u - v * u^2
@@ -43,8 +46,37 @@ kSaxis :: [(Double, Double)] -> P.Axis B D.V2 Double
 kSaxis xs = P.r2Axis &~ do
   P.linePlot' xs
 
+butcherTableauTex :: (Show a, Element a) => Matrix a -> String
+butcherTableauTex m = render $
+                    vcat [ text ("\n\\begin{array}{c|" ++ (concat $ replicate n "c") ++ "}")
+                         , us
+                         , text "\\end{array}"
+                         ]
+  where
+    n = rows m
+    rs = toLists m
+    ss = map (\r -> intercalate " & " $ map show r) rs
+    ts = zipWith (\n r -> "c_" ++ show n ++ " & " ++ r) [1..n] ss
+    us = vcat $ map (\r -> text r <+> text "\\\\") ts
+
 main :: IO ()
 main = do
+  -- $$
+  -- \begin{array}{c|cccc}
+  -- c_1    & a_{11} & a_{12}& \dots & a_{1s}\\
+  -- c_2    & a_{21} & a_{22}& \dots & a_{2s}\\
+  -- \vdots & \vdots & \vdots& \ddots& \vdots\\
+  -- c_s    & a_{s1} & a_{s2}& \dots & a_{ss} \\
+  -- \hline
+  --        & b_1    & b_2   & \dots & b_s\\
+  --        & b^*_1  & b^*_2 & \dots & b^*_s\\
+  -- \end{array}
+  -- $$
+
+  let res = btGet
+  putStrLn $ show res
+  putStrLn $ butcherTableauTex res
+  
   let res = odeSolve brusselator [1.2, 3.1, 3.0] (fromList [0.0, 0.1 .. 10.0])
   putStrLn $ show res
   renderRasterific "diagrams/brusselator.png"