1 files changed, 7 insertions, 0 deletions
diff --git a/src/SetSymmetry.c b/src/SetSymmetry.c
index 263af8d..c0742fc 100644
--- a/src/SetSymmetry.c
+++ b/src/SetSymmetry.c
@@ -59,6 +59,13 @@ int SetCartSymVI (const cGH *GH, const int *sym, int vi)
   DECLARE_CCTK_PARAMETERS
 
 
+  if (vi < 0 || vi >= CCTK_NumVars ())
+  {
+    CCTK_VWarn(1,__LINE__,__FILE__,CCTK_THORNSTRING,
+               "Invalid variable index %d in SetCartSymVI", vi);
+    return(-1);
+  }
+
   /* Pointer to the SymmetryGHextension */
   sGHex  = (SymmetryGHex *) CCTK_GHExtension (GH, "Symmetry");