diff --git a/stim/visualization/obj.h b/stim/visualization/obj.h
index efc4920..a9500bc 100644
--- a/stim/visualization/obj.h
+++ b/stim/visualization/obj.h
@@ -552,7 +552,7 @@ public:
 	}
 	std::vector< stim::vec<T> > getAllV(std::vector<unsigned> vertexIndices){
 		 std::vector< stim::vec<T> > allVerticesList;
-		 for (int i=0; i<numV(); i++)
+		 for (unsigned int i=0; i<numV(); i++)
 		 {
 			 vertexIndices[i] = i + 1;
 		 }
@@ -563,7 +563,7 @@ public:
 	getIndex(std::vector< stim::vec<T> >allVerticesList, stim::vec<T> v0) 
 	{
 		int result = 0;
-		for (int i = 0; i < allVerticesList.size() ; i++)
+		for (unsigned int i = 0; i < allVerticesList.size() ; i++)
 		{
 			if (allVerticesList[i] == v0) 
 			{
--
libgit2 0.21.4