Exercise from TMA4280, see p4.pdf for info
To build: create build folder in dir, enter build and enter: cmake .. To compile, enter make.
This compiles several exe-files. To run program with MPI: mpirun -np 4 ./sumvec_MPI , or sumvec_comb, -np 4 runs program with 4 processes. Number of processes must be a power of 2. To set number of threads when running OpenMP file: export OMP_NUM_THREADS=2