allow empty arrays

1 files changed, 2 insertions, 1 deletions

diff --git a/lib/Numeric/GSL/Vector.hs b/lib/Numeric/GSL/Vector.hs
index db34041..6204b8e 100644
--- a/lib/Numeric/GSL/Vector.hs
+++ b/lib/Numeric/GSL/Vector.hs
@@ -33,6 +33,7 @@ import Foreign.Marshal.Array(newArray)
 import Foreign.Ptr(Ptr)
 import Foreign.C.Types
 import System.IO.Unsafe(unsafePerformIO)
+import Control.Monad(when)
 
 fromei x = fromIntegral (fromEnum x) :: CInt
 
@@ -201,7 +202,7 @@ vectorMapValAux fun code val v = unsafePerformIO $ do
 
 vectorZipAux fun code u v = unsafePerformIO $ do
     r <- createVector (dim u)
-    app3 (fun (fromei code)) vec u vec v vec r "vectorZipAux"
+    when (dim u > 0) $ app3 (fun (fromei code)) vec u vec v vec r "vectorZipAux"
     return r
 
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