From d25da4df8cc2c3cf5535495d167378273026ca56 Mon Sep 17 00:00:00 2001
From: fredrikr79 <fredrikrobertsen7@gmail.com>
Date: Mon, 22 Sep 2025 16:33:07 +0200
Subject: [PATCH] ex3: task 1

---
 exercise3/wave_1d_parallel.c | 18 ++++++++++++++----
 1 file changed, 14 insertions(+), 4 deletions(-)

diff --git a/exercise3/wave_1d_parallel.c b/exercise3/wave_1d_parallel.c
index ef9847c..d81c084 100644
--- a/exercise3/wave_1d_parallel.c
+++ b/exercise3/wave_1d_parallel.c
@@ -9,7 +9,7 @@
 // TASK: T1a
 // Include the MPI headerfile
 // BEGIN: T1a
-;
+#include <mpi.h>
 // END: T1a
 
 // Option to change numerical precision.
@@ -19,7 +19,10 @@ typedef double real_t;
 // TASK: T1b
 // Declare variables each MPI process will need
 // BEGIN: T1b
-;
+#define ROOT 0
+int comm_size;
+int comm_rank;
+int_t n;
 // END: T1b
 
 // Simulation parameters: size, step count, and how often to save the state.
@@ -150,7 +153,14 @@ int main(int argc, char **argv) {
   // TASK: T1c
   // Initialise MPI
   // BEGIN: T1c
-  ;
+  MPI_Init(&argc, &argv);
+  MPI_Comm_rank(MPI_COMM_WORLD, &comm_rank);
+  MPI_Comm_size(MPI_COMM_WORLD, &comm_size);
+
+  n = N / comm_size;
+  int_t remr = N % comm_size;
+  if (comm_rank < remr)
+    n++;
   // END: T1c
 
   struct timeval t_start, t_end;
@@ -168,7 +178,7 @@ int main(int argc, char **argv) {
   // TASK: T1d
   // Finalise MPI
   // BEGIN: T1d
-  ;
+  MPI_Finalize();
   // END: T1d
 
   exit(EXIT_SUCCESS);