1. Examples
Copy example files to your home directory.
1. Login to HPC
2. Copy
cp -r /project/xuehaiqi_652/examples .
3. Goto examples cd examples
The openmp_example.c contains the OpenMP implementation of matrix vector multiplication.
1. Login to HPC
2. Compile
gcc -O3 -fopenmp openmp_example.c
3. Run
srun -c8 ./a.out
The option -c specifies the number of CPUs allocated for a task. By default, the value is 1. For OpenMP program, the number of threads should equal the number of CPUs.
The mpi_examples folder includes the source codes used in discussions. To run an mpi
program, for example, the ‘scatter.c’, follow the steps:
1. Login to HPC
2. Setup MPI toolchain:
module purge module load intel/19.0.4 intel-mpi
3. Compile
mpicc -O3 scatter.c
4. Run
srun --exclusive --mpi=pmi2 -n4 ./a.out
The option -n specifies the number of tasks (processes). By default, the value is 1. There is 1 task per node (machine), but note that the -c option will change this default.
2. Parallel Matrix Multiplication[50 points]
Parallelize the naive matrix multiplication which you implemented in PA 1 using OpenMP. Name the program as openmp.c. Take a screenshot.
• The matrix size is 4K × 4K. Print out the execution time and the value of C[100][100] in your program.
• Pass the number of threads p as a command line parameter [1].
• Report the execution time for p = 1, 2, 4.
3. Pass Message in a Ring [50 points]
Write an MPI program that passes a value around 4 processes using the following steps.
Name this program as mpi.c. Take a screenshot.
1. Process 0 initializes Msg = 451 and prints value of Msg
2. Process 0 sends the value of Msg to Process 1
3. Process 1 receives the value of Msg, increases it by 1, prints the value and sends the current value of Msg to Process 2
4. Process 2 receives the value of Msg, increases it by 1, prints the value and sends the current value of Msg to Process 3
5. Process 3 receives the value of Msg, increases it by 1, prints the value and sends the current value of Msg to Process 0
6. Process 0 receives the value of Msg from Process 3 and prints the value
The output messages look like (Note that your code is still correct if the order of messages is different):
• Process 0: Initially Msg = 451
• Process 1: Msg = 452
• Process 3: Msg = 454
• Process 2: Msg = 453
• Process 0: Received Msg = 454. Done!
