Biowulf High Performance Computing at the NIH
CaVEMan on Biowulf

Single nucleotide variant (SNV) expectation maximisation based mutation calling algorithm aimed at detecting somatic mutations in paired (tumour/normal) cancer samples. Supports both bam and cram format via htslib


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 caveman

[user@cn3144 ~]$ mkdir /data/$USER/caveman; cd /data/$USER/caveman
Copy sample data to the current folder:
[user@cn3144 ~]$ cp -r $CAVEMAN_DATA . 
This command will create a data folder test_data in the current directory. Processing of the data by cavemen can be performed in five steps described in the documentation and reproduced below.

Step 1:
[user@cn3144 ~]$ caveman setup -t test_data/test_mt.bam -n test_data/test_wt.bam -r test_data/genome.fa.fai -g test_data/ign.test
- files ./caveman.cfg.ini and ./alg_bean will be produced in the current directory.

Step 2:
[user@cn3144 ~]$ caveman split -i 1
- file ./splitList.1 will be produced.

For the further processing, the name of the splitList file should be the same as specified in the file ./caveman.cfg.ini, so one should either to
- edit the file ./caveman.cfg.ini accordinglty, or
- store the contents of the file(s) splitList.* in a file splitList:
[user@cn3144 ~]$ cat ./splitList.* > splitList
Step 3:
[user@cn3144 ~]$ caveman mstep -i 1
Folder ./results/1 will be created.

Step 4:
[user@cn3144 ~]$ caveman merge
- files probs_arr and covs_arr will be created in the current folder.

Step 5:
[user@cn3144 ~]$ caveman estep -i 1  -v 37/GRCh37  -w human
More files will be produced in the folder results/1. Note that specifying the options -v and -w is obligatory for this step.
[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 caveman
for i in {1..2}; do
      caveman split -i $i
cat splitList.? > splitList
for i in {1..2}; do
      caveman mstep -i $i
caveman merge
for i in {1..2}; do
      caveman estep -i $i

Submit this job using the Slurm sbatch command.

sbatch  [--mem=#g]