add first part of hands-on ex

lectures/parallelism/slides.qmd

@@ -67,24 +67,31 @@ FIXME
         a[i] = 2 * i;
 ```
 
-## Hands-on Session! {background-color=var(--dark-bg-color) .leftalign}
-1. Load the GNU compliler and compile the code on Levante
+# Hands-on Session! {background-color=var(--dark-bg-color) .leftalign}
+1. Load the GNU compiler on Levante
 ```bash
 module load gcc
-g++ main.cpp -o main
 ```
+2. Compile and run the serial example 
+```bash
+gcc main.c -o serial.x -lm 
+time ./serial.x   # use `time` to check the runtime
+```
+3. Compile and run the example using OpenMP
+```bash
+gcc -fopenmp main.c -o parallel.x -lm 
+OMP_NUM_THREADS=2 time ./parallel.x 
+```
+4. See next slide!
 
-
-1. Compile and run the example serially. Use `time ./serial.x` to time the execution.
-23. Compile and run the example using OpenMP. Use `OMP_NUM_THREADS=2 time ./omp.x` to time the execution.
-42. Now add
+# Hands-on Session! {background-color=var(--dark-bg-color) .leftalign}
+4. Now add
    * `schedule(static,1)`
    * `schedule(static,10)`
    * `schedule(FIXMEsomethingelse)`
    * `schedule(FIXMEsomethingelse)`
 and find out how the OpenMP runtime decomposes the problem domain.
 
-FIXME: Maybe get rid of timings here?
 FIXME: Maybe add something varying the number of threads, so that one can see
 first ideas of strong/weak scaling.