From 7c00bf20bf046f012840d690865d56c82c20bf23 Mon Sep 17 00:00:00 2001
From: fredrikr79 <fredrikrobertsen7@gmail.com>
Date: Mon, 22 Sep 2025 19:46:32 +0200
Subject: [PATCH] ex3: task 8

---
 exercise3/wave_1d_parallel.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/exercise3/wave_1d_parallel.c b/exercise3/wave_1d_parallel.c
index ef9847c..2aaa42d 100644
--- a/exercise3/wave_1d_parallel.c
+++ b/exercise3/wave_1d_parallel.c
@@ -50,6 +50,8 @@ real_t
 // Save the present time step in a numbered file under 'data/'.
 void domain_save(int_t step) {
   // BEGIN: T8
+  if (comm_rank != ROOT)
+    return;
   char filename[256];
   sprintf(filename, "data/%.5ld.dat", step);
   FILE *out = fopen(filename, "wb");