Setup Parallel Computing Lab on Ubuntu

Step 1: Open Terminal:

• Press Ctrl + Alt + T to open the Terminal on Ubuntu.

Step 2: Install GCC, G++, OpenMP, and MPI packages:

• Copy and paste this command in your terminal:

sudo apt update && sudo apt upgrade -y && sudo apt install -y build-essential gcc g++ gfortran openmpi-bin openmpi-common libopenmpi-dev

sudo apt update && sudo apt upgrade -y && sudo apt install -y build-essential gcc g++ gfortran openmpi-bin openmpi-common libopenmpi-dev

What it does:

• apt update: Updates package list
• apt upgrade -y: Upgrades installed packages
• apt install: Installs:
  • gcc, g++: For C/C++
  • gfortran: For Fortran
  • openmpi-*: For MPI (compiler and runtime)
  • build-essential: Compiler tools (make, linker, etc.)

Step 3: Install Gedit (Text Editor):

sudo apt install -y gedit

sudo apt install -y gedit

Step 4: Write Your Code:

• You can create and open a file like this and paste or write your code:

▶ For OpenMP (1-4 Programs only):

gedit openmp_hello.c

gedit openmp_hello.c

▶ For MPI (6-9 Programs only):

gedit openmpi_hello.c

gedit openmpi_hello.c

Step 5: Compile the Code:

▶ Compile OpenMP:

gcc -fopenmp openmp_hello.c -o openmp_hello

gcc -fopenmp openmp_hello.c -o openmp_hello

• gcc → GNU C Compiler
• -fopenmp → Enables OpenMP support in the compiler
• openmp_hello.c → The source code file to compile
• -o openmp_hello → Names the output executable as “openmp_hello”

▶ Compile MPI:

mpicc mpi_hello.c -o mpi_hello

mpicc mpi_hello.c -o mpi_hello

• mpicc → MPI C compiler (wrapper for gcc with MPI support)
• mpi_hello.c → The source code file to compile
• -o mpi_hello → Names the output executable as “mpi_hello”

Step 6: Run the Program:

▶ Run OpenMP:

OMP_NUM_THREADS=4 && ./mpi_hello

OMP_NUM_THREADS=4 && ./mpi_hello

• OMP_NUM_THREADS=4 → Sets the number of OpenMP threads to 4 (for hybrid MPI + OpenMP programs)
• && → Executes the next command only if the previous one runs successfully.
• ./mpi_hello → Runs the compiled MPI (or hybrid MPI+OpenMP) executable

▶ Run MPI:

mpirun -np 4 ./mpi_hello

mpirun -np 4 ./mpi_hello

• mpirun → Runs an MPI program using multiple processes
• -np 4 → Specifies to run with 4 parallel processes
• ./mpi_hello → The compiled MPI executable to run