diff --git a/src/metis-5.1.0/include/metis.h b/src/metis-5.1.0/include/metis.h
index dc5406ae5..634a2f0c6 100644
--- a/src/metis-5.1.0/include/metis.h
+++ b/src/metis-5.1.0/include/metis.h
@@ -30,7 +30,7 @@
  GCC does provides these definitions in stdint.h, but it may require some
  modifications on other architectures.
 --------------------------------------------------------------------------*/
-#define IDXTYPEWIDTH 32
+#define IDXTYPEWIDTH 64
 
 
 /*--------------------------------------------------------------------------