Biowulf High Performance Computing at the NIH
SNP-SITES on Biowulf

SNP-sites extracts single nucleotide polymorphisms (SNPs) from a multi-FASTA alignment outputs results in multiple formats for downstream analysis.


Important Notes

Interactive job
Interactive jobs should be used for debugging, graphics, or applications that cannot be run as batch jobs.

Allocate an interactive session and run the program.
Sample session (user input in bold):

[user@biowulf]$ sinteractive
salloc.exe: Pending job allocation 46116226
salloc.exe: job 46116226 queued and waiting for resources
salloc.exe: job 46116226 has been allocated resources
salloc.exe: Granted job allocation 46116226
salloc.exe: Waiting for resource configuration
salloc.exe: Nodes cn3144 are ready for job

[user@cn3144 ~]$ module load snp-sites
[+] Loading singularity  3.4.2  on cn3103 
[+] Loading snp-sites 2.4.1  ... 

[user@cn3144 ~]$ cd /data/user/SNP-SITES_TEST

[user@cn3144 ~]$ snp-sites PMEN1.aln.gz > PMEN1.out

[user@cn3144 ~]$ exit
salloc.exe: Relinquishing job allocation 46116226
[user@biowulf ~]$

Batch job
Most jobs should be run as batch jobs.

Create a batch input file (e.g. For example:

set -e
module load snp-sites
snp-sites /data/user/SNP-SITES_TEST/PMEN1.aln.gz > /data/user/SNP-SITES_TEST/PMEN1.out

Submit this job using the Slurm sbatch command.

sbatch [--cpus-per-task=#] [--mem=#]
Swarm of Jobs
A swarm of jobs is an easy way to submit a set of independent commands requiring identical resources.

Create a swarmfile (e.g. snp-sites.swarm). For example:

snp-sites /data/user/SNP-SITES_TEST/PMEN1.aln.gz > /data/user/SNP-SITES_TEST/PMEN1.out
snp-sites /data/user/SNP-SITES_TEST/ST239.aln.gz > /data/user/SNP-SITES_TEST/ST239.out

Submit this job using the swarm command.

swarm -f snp-sites.swarm [-g #] [-t #] --module snp-sites
-g # Number of Gigabytes of memory required for each process (1 line in the swarm command file)
-t # Number of threads/CPUs required for each process (1 line in the swarm command file).
--module snp-sites Loads the snp-sites module for each subjob in the swarm