| Table of Contents | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
|
...
| Code Block | ||
|---|---|---|
| ||
# List all files and directories in the scratch directory
ls /midtier/labname/scratch/
# Navigate to a specific subdirectory
cd /midtier/labname/scratch/cwid
# Copy a file from the current directory to another directory
cp data.txt /midtier/labname/scratch/cwid/
# Move the copied file to a different directory
mv /midtier/labname/scratch/cwid/data.txt /midtier/labname/scratch/backup/
# Create a new directory
mkdir /midtier/labname/scratch/cwid/new_project/ |
Code example
To illustrate how to run computational jobs, consider the following toy problem, that is implemented in C. It estimates value of π using a random sampling method:
Generate random points (x, y) in a unit square (0 ≤ x, y ≤ 1).
Count how many points fall inside the quarter circle (x² + y² ≤ 1).
The ratio of points inside the circle to total points approximates π: π≈4 × total points / points inside circle
| Code Block | ||
|---|---|---|
| ||
#include <stdio.h> #include <stdlib.h> #include <math.h> #include <omp.h> long long monte_carlo_pi(long long num_samples, int num_threads) { long long inside_circle = 0; #pragma omp parallel num_threads(num_threads) { unsigned int seed = 1234 + omp_get_thread_num(); // Unique seed for each thread long long local_count = 0; #pragma omp for for (long long i = 0; i < num_samples; i++) { double x = (double)rand_r(&seed) / RAND_MAX; double y = (double)rand_r(&seed) / RAND_MAX; if (x * x + y * y <= 1.0) { local_count++; } } #pragma omp atomic inside_circle += local_count; } return inside_circle; } int main(int argc, char *argv[]) { if (argc != 3) { printf("Usage: %s <num_samples> <num_threads>\n", argv[0]); return 1; } long long num_samples = atoll(argv[1]); // Number of random points int num_threads = atoi(argv[2]); // Number of OpenMP threads double start_time = omp_get_wtime(); long long inside_circle = monte_carlo_pi(num_samples, num_threads); double end_time = omp_get_wtime(); double pi_approx = 4.0 * (double)inside_circle / num_samples; printf("Approximated π: %.15f\n", pi_approx); printf("Error: %.15f\n", fabs(pi_approx - 3.141592653589793)); printf("Execution Time: %.6f seconds\n", end_time - start_time); return 0; } |
Save this code into a file code.c and compile using a command
| Code Block |
|---|
gcc -fopenmp code.c |
it will generate an executable a.out that we will use to illustrate how to submit jobs
Running jobs
Computational jobs on the AI cluster are managed with a SLURM job manager. We provide an in-depth tutorial on how to use SLURM <placeholder>, but some basic examples that are immediately applicable on the AI cluster will be discussed in this section.
Important notice:
| Warning |
|---|
Do not run computations on login nodes |
...