[SOLVED] EE451 Assignment 4

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 multi- plication.

1. Login to HPC
2. Compile

   gcc -O3 -fopenmp openmp_example.c

3. Run

   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:

srun -c8 ./a.out

1. Login to HPC
2. Setup MPI toolchain:

3. Compile

mpicc -O3 scatter.c

4. Run

module purge
module load intel/19.0.4 intel-mpi

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
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!