diff --git a/contrib/DiscreteIntegration/DILevelset.h b/contrib/DiscreteIntegration/DILevelset.h
index 2647cbb72745db146c19bcc61c3ce836c13372a8..55ae3d702ae8161a1ae50124346b94201c633f3e 100644
--- a/contrib/DiscreteIntegration/DILevelset.h
+++ b/contrib/DiscreteIntegration/DILevelset.h
@@ -1,7 +1,7 @@
 #ifndef _gLEVELSET_H_
 #define _gLEVELSET_H_
 
-#include <cmath>
+#include <math.h>
 #include <vector>
 #include <stdio.h>
 
@@ -79,7 +79,7 @@ public:
   gLevelsetPrimitive(int &tag) {
     if (tag < 1) {
       printf("Tag of the levelset (%d) must be greater than 0.\n", tag);
-      tag = std::fabs(tag);
+      tag = fabs(tag);
     }
     tag_ = tag++;
   }