egs: sync the residual maximum across components.

1 files changed, 7 insertions, 0 deletions

diff --git a/ell_grid_solve.c b/ell_grid_solve.c
index 97b8688..c3ce3a7 100644
--- a/ell_grid_solve.c
+++ b/ell_grid_solve.c
@@ -186,6 +186,13 @@ static void residual_calc(EGSContext *ctx, int export_res)
 
     mg2di_timer_stop(&ctx->timer_res_calc);
 
+    if (priv->dg->nb_components > 1) {
+        mg2di_timer_start(&ctx->timer_mpi_sync);
+        MPI_Allreduce(MPI_IN_PLACE, &ctx->residual_max, 1,
+                      MPI_DOUBLE, MPI_MAX, priv->comm);
+        mg2di_timer_stop(&ctx->timer_mpi_sync);
+    }
+
     priv->reflect_skip = ~0;
 }