From 1cf2a0c4e4c54da1e66e2c6dedb5db7a4e951010 Mon Sep 17 00:00:00 2001
From: Aditya Trivedi <adit4443ya@gmail.com>
Date: Mon, 31 Mar 2025 23:10:03 +0530
Subject: [PATCH] Test: Add MPI_Reduce test

---
 tests/reduce_1.f90 | 26 ++++++++++++++++++++++++++
 1 file changed, 26 insertions(+)
 create mode 100644 tests/reduce_1.f90

diff --git a/tests/reduce_1.f90 b/tests/reduce_1.f90
new file mode 100644
index 0000000..6e29b4a
--- /dev/null
+++ b/tests/reduce_1.f90
@@ -0,0 +1,26 @@
+program test_reduce
+    use mpi
+    implicit none
+
+    integer :: ierr, rank, comm, root
+    integer :: sendval, recvval
+
+    comm = MPI_COMM_WORLD
+    root = 0
+
+    call MPI_Init(ierr)
+    call MPI_Comm_rank(comm, rank, ierr)
+
+    ! Each rank will hold its rank ID in 'sendval'
+    sendval = rank
+    recvval = -999  ! dummy init
+
+    ! We do a sum over all ranks
+    call MPI_Reduce(sendval, recvval, 1, MPI_INTEGER, MPI_SUM, root, comm, ierr)
+
+    if (rank == root) then
+        print *, "Root received sum of ranks = ", recvval
+    end if
+
+    call MPI_Finalize(ierr)
+end program test_reduce
\ No newline at end of file