diff --git a/src/compute_omega_chunk.cpp b/src/compute_omega_chunk.cpp
index 50f7db7aa7..a924cef208 100644
--- a/src/compute_omega_chunk.cpp
+++ b/src/compute_omega_chunk.cpp
@@ -83,7 +83,7 @@ void ComputeOmegaChunk::init()
 
 void ComputeOmegaChunk::compute_array()
 {
-  int i,j,index;
+  int i,j,m,index;
   double dx,dy,dz,massone;
   double unwrap[3];