diff --git a/Applications/BipartiteMatchings/BPMaximalMatching.cpp b/Applications/BipartiteMatchings/BPMaximalMatching.cpp
index d116e761..0b2cc1d0 100644
--- a/Applications/BipartiteMatchings/BPMaximalMatching.cpp
+++ b/Applications/BipartiteMatchings/BPMaximalMatching.cpp
@@ -70,8 +70,9 @@ void removeIsolated(PSpMat_Bool & A)
 {
     
     int nprocs, myrank;
-    MPI_Comm_size(MPI_COMM_WORLD,&nprocs);
-    MPI_Comm_rank(MPI_COMM_WORLD,&myrank);
+    MPI_Comm comm = A.getcommgrid()->GetWorld();
+    MPI_Comm_size(comm,&nprocs);
+    MPI_Comm_rank(comm,&myrank);
     
     
     FullyDistVec<int64_t, int64_t> * ColSums = new FullyDistVec<int64_t, int64_t>(A.getcommgrid());
@@ -121,7 +122,7 @@ void removeIsolated(PSpMat_Bool & A)
         cout << nrows2 << " " << ncols2 << " " << nnz2 << " " << avgDeg2 << " \n";
     }
     
-    MPI_Barrier(MPI_COMM_WORLD);
+    MPI_Barrier(comm);
     
     
 }
diff --git a/Applications/BipartiteMatchings/BPMaximalMatching.h b/Applications/BipartiteMatchings/BPMaximalMatching.h
index eef74142..01ee8551 100644
--- a/Applications/BipartiteMatchings/BPMaximalMatching.h
+++ b/Applications/BipartiteMatchings/BPMaximalMatching.h
@@ -26,8 +26,9 @@ void MaximalMatching(Par_DCSC_Bool & A, Par_DCSC_Bool & AT, FullyDistVec<IT, IT>
 {
 
 	typedef VertexTypeML < IT, IT> VertexType;
-    MPI_Comm comm = A.getcommgrid()->GetWorld();
+    
     int nprocs, myrank;
+    MPI_Comm comm = A.getcommgrid()->GetWorld();
     MPI_Comm_size(comm,&nprocs);
     MPI_Comm_rank(comm,&myrank);
     int nthreads = 1;
diff --git a/Applications/BipartiteMatchings/BPMaximumMatching.cpp b/Applications/BipartiteMatchings/BPMaximumMatching.cpp
index b917ca7d..4b168f24 100644
--- a/Applications/BipartiteMatchings/BPMaximumMatching.cpp
+++ b/Applications/BipartiteMatchings/BPMaximumMatching.cpp
@@ -49,8 +49,9 @@ void removeIsolated(Par_DCSC_Bool & A)
 {
     
     int nprocs, myrank;
-    MPI_Comm_size(MPI_COMM_WORLD,&nprocs);
-    MPI_Comm_rank(MPI_COMM_WORLD,&myrank);
+    MPI_Comm comm = A.getcommgrid()->GetWorld();
+    MPI_Comm_size(comm,&nprocs);
+    MPI_Comm_rank(comm,&myrank);
     
     
     FullyDistVec<int64_t, int64_t> * ColSums = new FullyDistVec<int64_t, int64_t>(A.getcommgrid());
@@ -100,7 +101,7 @@ void removeIsolated(Par_DCSC_Bool & A)
         cout << nrows2 << " " << ncols2 << " " << nnz2 << " " << avgDeg2 << " \n";
     }
     
-    MPI_Barrier(MPI_COMM_WORLD);
+    MPI_Barrier(comm);
     
     
 }
@@ -282,8 +283,9 @@ void experiment_maximal(Par_DCSC_Bool & A, Par_DCSC_Bool & AT, FullyDistVec<int6
 {
     
     int nprocs, myrank;
-    MPI_Comm_size(MPI_COMM_WORLD,&nprocs);
-    MPI_Comm_rank(MPI_COMM_WORLD,&myrank);
+    MPI_Comm comm = A.getcommgrid()->GetWorld();
+    MPI_Comm_size(comm,&nprocs);
+    MPI_Comm_rank(comm,&myrank);
     
     FullyDistVec<int64_t, int64_t> mateRow2Col ( A.getcommgrid(), A.getnrow(), (int64_t) -1);
     FullyDistVec<int64_t, int64_t> mateCol2Row ( A.getcommgrid(), A.getncol(), (int64_t) -1);
diff --git a/Applications/BipartiteMatchings/BPMaximumMatching.h b/Applications/BipartiteMatchings/BPMaximumMatching.h
index 86ff625f..9d66823a 100644
--- a/Applications/BipartiteMatchings/BPMaximumMatching.h
+++ b/Applications/BipartiteMatchings/BPMaximumMatching.h
@@ -183,9 +183,10 @@ void AugmentPath(FullyDistVec<IT, IT>& mateRow2Col, FullyDistVec<IT, IT>& mateCo
     IT locind_row, locind_col;
     int myrank;
     
-    MPI_Comm_rank(MPI_COMM_WORLD, &myrank);
-    
-    
+    MPI_Comm comm = mateRow2Col.getcommgrid()->GetWorld();
+    MPI_Comm_rank(comm,&myrank);
+
+
     for(IT i=0; i<leaves.LocArrSize(); i++)
     {
         int depth=0;
@@ -244,8 +245,9 @@ void maximumMatching(SpParMat < IT, NT, DER > & A, FullyDistVec<IT, IT>& mateRow
     
     double tstart = MPI_Wtime();
     int nprocs, myrank;
-    MPI_Comm_size(MPI_COMM_WORLD,&nprocs);
-    MPI_Comm_rank(MPI_COMM_WORLD,&myrank);
+    MPI_Comm comm = A.getcommgrid()->GetWorld();
+    MPI_Comm_size(comm,&nprocs);
+    MPI_Comm_rank(comm,&myrank);
     
     IT nrow = A.getnrow();
     IT ncol = A.getncol();