diff --git a/projects/rccl/tools/topo_expl/topo_expl.cpp b/projects/rccl/tools/topo_expl/topo_expl.cpp
index 555bb28225..1f87fa0646 100644
--- a/projects/rccl/tools/topo_expl/topo_expl.cpp
+++ b/projects/rccl/tools/topo_expl/topo_expl.cpp
@@ -209,20 +209,30 @@ int main(int argc,char* argv[])
     bootstrapAllGather(&comm[i], allGather1Data);
   }
 
-  struct ncclTopoGraph treeGraph, ringGraph, collNetGraph;
-
-  for (int i = 0; i < nranks; i++) {
-    node_model = network.GetNode(i);
-    assert(node_model!=0);
-    initTransportsRank_1(&comm[i], allGather1Data, allGather3Data, treeGraph, ringGraph, collNetGraph);
+  struct ncclTopoGraph *treeGraph, *ringGraph, *collNetGraph;
+  treeGraph = (struct ncclTopoGraph *)malloc(sizeof(struct ncclTopoGraph)*nranks);
+  ringGraph = (struct ncclTopoGraph *)malloc(sizeof(struct ncclTopoGraph)*nranks);
+  collNetGraph = (struct ncclTopoGraph *)malloc(sizeof(struct ncclTopoGraph)*nranks);
+  if (!treeGraph || !ringGraph || !collNetGraph) {
+    printf("Failed to allocate memory for graphs\n");
+    return -1;
   }
 
   for (int i = 0; i < nranks; i++) {
     node_model = network.GetNode(i);
     assert(node_model!=0);
-    initTransportsRank_3(&comm[i], allGather3Data, treeGraph, ringGraph, collNetGraph);
+    initTransportsRank_1(&comm[i], allGather1Data, allGather3Data, treeGraph[i], ringGraph[i], collNetGraph[i]);
   }
 
+  for (int i = 0; i < nranks; i++) {
+    node_model = network.GetNode(i);
+    assert(node_model!=0);
+    initTransportsRank_3(&comm[i], allGather3Data, treeGraph[i], ringGraph[i], collNetGraph[i]);
+  }
+
+  free(treeGraph);
+  free(ringGraph);
+  free(collNetGraph);
   free(allGather3Data);
   free(allGather1Data);