1 files changed, 32 insertions, 0 deletions

diff --git a/examples/devel/ej2/wrappers.hs b/examples/devel/ej2/wrappers.hs
new file mode 100644
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+++ b/examples/devel/ej2/wrappers.hs
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+{-# LANGUAGE ForeignFunctionInterface #-}
+
+-- $ ghc -O2 --make wrappers.hs functions.c
+
+import Numeric.LinearAlgebra
+import Data.Packed.Development
+import Foreign(Ptr,unsafePerformIO)
+import Foreign.C.Types(CInt)
+
+-----------------------------------------------------
+
+main = do
+    print $ myDiag $ (3><5) [1..]
+
+-----------------------------------------------------
+-- arbitrary data order
+
+foreign import ccall unsafe "c_diag"
+    cDiag :: CInt                        -- matrix order
+          -> CInt -> CInt -> Ptr Double  -- argument
+          -> CInt -> Ptr Double          -- result1
+          -> CInt -> CInt -> Ptr Double  -- result2
+          -> IO CInt                     -- exit code
+
+myDiag m = unsafePerformIO $ do
+    y <- createVector (min r c)
+    z <- createMatrix (orderOf m) r c
+    app3 (cDiag o) mat m vec y mat z "cDiag"
+    return (y,z)
+  where r = rows m
+        c = cols m
+        o = if orderOf m == RowMajor then 1 else 0