1 files changed, 7 insertions, 0 deletions
diff --git a/src/GetSymmetry.c b/src/GetSymmetry.c
index f21a3ee..5224a96 100644
--- a/src/GetSymmetry.c
+++ b/src/GetSymmetry.c
@@ -57,6 +57,13 @@ int GetCartSymVI(const cGH *GH, 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 GetCartSymVI", vi);
+    return(-1);
+  }
+
   /* Pointer to the SymmetryGHextension */
   sGHex = (SymmetryGHex *)CCTK_GHExtension(GH, "Symmetry");