egs: sync the residual maximum across components.

1 files changed, 2 insertions, 2 deletions

diff --git a/relax_mpi_test.c b/relax_mpi_test.c
index 75e76ef..5e69b49 100644
--- a/relax_mpi_test.c
+++ b/relax_mpi_test.c
@@ -190,7 +190,7 @@ int main(int argc, char **argv)
         goto fail;
     }
 
-    MPI_Reduce(&ctx->residual_max, &res_old, 1, MPI_DOUBLE, MPI_MAX, 0, MPI_COMM_WORLD);
+    res_old = ctx->residual_max;
 
     for (int i = 0; i < maxiter; i++) {
         ret = mg2di_egs_solve(ctx, EGS_SOLVE_RELAXATION, 0);
@@ -199,7 +199,7 @@ int main(int argc, char **argv)
             ret = 1;
             goto fail;
         }
-        MPI_Reduce(&ctx->residual_max, &res_new, 1, MPI_DOUBLE, MPI_MAX, 0, MPI_COMM_WORLD);
+        res_new = ctx->residual_max;
         if (rank == 0) {
             if (res_new > 1e3) {
                 fprintf(stderr, "Diverged at step %d: %g -> %g\n", i, res_old, res_new);