Picard

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Description

picard website  

SAM (Sequence Alignment/Map) format is a generic format for storing large nucleotide sequence alignments. SAM is described in the SAMtools project page.

Picard comprises Java-based command-line utilities that manipulate SAM files, and a Java API (SAM-JDK) for creating new programs that read and write SAM files. Both SAM text format and SAM binary (BAM) format are supported.

Picard does not have its own mailing lists. Please use the SAMTools mailing Lists for Picard-related correspondence.

Required Modules

modules documentation

Serial

  • picard

System Variables

  • HPC_{{#uppercase:picard}}_DIR - installation directory

Additional Information

See the samtools HPC wiki page for more details on Samtools.

There is a convenience symlink to the latest picard directory in the addition to the $HPC_PICARD_DIR set by the picard module as

/apps/picard/bin

So picard jars can be run both as

java -Xms1g -Xmx8g -jar /apps/picard/bin/ReorderSam.jar

and

java -Xms1g -Xmx8g -jar $HPC_PICARD_DIR/ReorderSam.jar

To run picard tools with non-default java memory settings you can set the minimum and the maximum heap memory in the command. For example:

java -Xms1g -Xmx8g -jar /apps/picard/bin/ReorderSam.jar INPUT=input.bam OUTPUT=output.bam VALIDATION_STRINGENCY=LENIENT REFERENCE=ref.fasta CREATE_INDEX=true

Starting with picard/1.137 use the following:

picard CreateSequenceDictionary R=example.fa O=example.dict

Picard Java Garbage Collection thread use

As a Java-based application, Picard uses extra threads for Garbage Collection (GC--memory management). We have observed that these threads can use a significant percentage of CPU resources, bringing Picard's total CPU utilization to as high as 6 CPUs. This issue is discussed in this Picard FAQ. In a scheduled environment it is critical that all resources used by the application are requested at the time of submission. Please make sure to account for this in formulating the job resource request, as well as using Java's GC management flag (-XX:ParallelGCThreads=<number of threads> ) to appropriately limit GC. As a start, we recommend a resource request and GC flag along the lines of:

#PBS -l nodes=1:ppn=6

and

java -Xms1g -Xmx8g -XX:ParallelGCThreads=5 -jar $HPC_PICARD_DIR/ReorderSam.jar

Resource use during a job can be monitored with the showq -r -u <username>. The "EFFIC" column shows job efficiency. Numbers over 100 indicate your job is using more resources than requested. If efficiency is consistently well below 100, you can ramp back the above resource and -XX:ParallelGCThreads requests.