Add example to print Butcher Tableaux

2 files changed, 55 insertions, 0 deletions

diff --git a/examples/ButcherTableau.hs b/examples/ButcherTableau.hs
new file mode 100644
index 0000000..e667ef1
--- /dev/null
+++ b/examples/ButcherTableau.hs
@@ -0,0 +1,47 @@
+{-# OPTIONS_GHC -Wall #-}
+
+import           Numeric.Sundials.ARKode.ODE
+import           Numeric.LinearAlgebra
+
+import           Data.List (intercalate)
+
+import           Text.PrettyPrint.HughesPJClass
+
+
+butcherTableauTex :: ButcherTable -> String
+butcherTableauTex (ButcherTable m c b b2) =
+  render $
+  vcat [ text ("\n\\begin{array}{c|" ++ (concat $ replicate n "c") ++ "}")
+       , us
+       , text "\\hline"
+       , text bs <+> text "\\\\"
+       , text b2s <+> text "\\\\"
+       , text "\\end{array}"
+       ]
+  where
+    n = rows m
+    rs = toLists m
+    ss = map (\r -> intercalate " & " $ map show r) rs
+    ts = zipWith (\i r -> show i ++ " & " ++ r) (toList c) ss
+    us = vcat $ map (\r -> text r <+> text "\\\\") ts
+    bs  = " & " ++ (intercalate " & " $ map show $ toList b)
+    b2s = " & " ++ (intercalate " & " $ map show $ toList b2)
+
+main :: IO ()
+main = do
+
+  let res = butcherTable (SDIRK_2_1_2 undefined)
+  putStrLn $ show res
+  putStrLn $ butcherTableauTex res
+
+  let resA = butcherTable (KVAERNO_4_2_3 undefined)
+  putStrLn $ show resA
+  putStrLn $ butcherTableauTex resA
+
+  let resB = butcherTable (SDIRK_5_3_4 undefined)
+  putStrLn $ show resB
+  putStrLn $ butcherTableauTex resB
+
+  let resC = butcherTable (FEHLBERG_6_4_5 undefined)
+  putStrLn $ show resC
+  putStrLn $ butcherTableauTex resC
diff --git a/examples/examples.cabal b/examples/examples.cabal
index c2fed7e..5e85a3d 100644
--- a/examples/examples.cabal
+++ b/examples/examples.cabal
@@ -19,3 +19,11 @@ executable sundials
                        hmatrix-sundials,
                        hmatrix-gsl
   default-language:    Haskell2010
+
+executable butcherTableau
+  main-is:             ButcherTableau.hs
+  build-depends:       base >=4.10 && <4.11,
+                       hmatrix,
+                       hmatrix-sundials,
+                       pretty
+  default-language:    Haskell2010