# Tagged with #variantcontext 1 documentation article | 0 announcements | 2 forum discussions

The picard repository on github contains all picard public tools. Libraries live under the htsjdk, which includes the samtools-jdk, tribble, and variant packages (which includes VariantContext and associated classes as well as the VCF/BCF codecs).

If you just need to check out the sources and don't need to make any commits into the picard repository, the command is:

git clone https://github.com/broadinstitute/picard.git


Then within the picard directory, clone the htsjdk.

cd picard
git clone https://github.com/samtools/htsjdk.git


Then you can attach the picard/src/java and picard/htsjdk/src/java directories in IntelliJ as a source directory (File -> Project Structure -> Libraries -> Click the plus sign -> "Attach Files or Directories" in the latest IntelliJ).

To build picard and the htsjdk all at once, type ant from within the picard directory. To run tests, type ant test

If you do need to make commits into the picard repository, first you'll need to create a github account, fork picard or htsjdk, make your changes, and then issue a pull request. For more info on pull requests, see: https://help.github.com/articles/using-pull-requests

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I was pulling my hair out over this one.

I was applying a hard filter to a genotyped gVCF using JEXL to access variant context attributes to decide what filter setting I would apply. The filter was

"vc.getGenotype("%sample%").isHomRef() ? vc.getGenotype("%sample%").getAD().size() == 1 ? DP < 10 : ( DP - MQ0 ) < 10 or ( MQ0 - (1.0 * DP) ) >= 0.1 or MQRankSum <= 3.2905 or ReadPosRankSum >= 3.2905 or BaseQRankSum >= 2.81 : false"

In pseudocode it says:

 if ( isHomRef ) then
if ( getAD().size() == 1 ) then DP < 10 else
( DP - MQ0 ) < 10 or ( MQ0 - (1.0 * DP) ) >= 0.1 or MQRankSum >= 3.2905 or ReadPosRankSum >= 3.2905 or BaseQRankSum >= 2.81 else ignore record


The idea being that for records where not all reads contained the reference allele, we would filter out those positions where there was evidence to suggest that the reads supporting an alternate allele were of a significantly better quality. However, running this filter I keep getting the warning (snipped for clarity):

WARN [SNIP]... MQRankSum <= 3.2905 [SNIP]... : false;' undefined variable MQRankSum

So I thought the filter was failing. However, just as a test, I changed the direction of MQRankSum from >=3.2905 to <=3.2905 (a bit nonsensical, it should basically apply the filter to almost all HomRef positions that had any reads supporting an alternate allele).

I still get the warning but I found the filter was applied to variant records as it should be. e.g. the following went from PASS to BAD_HOMREF:

So the filter is being correctly applied, but I am not sure why all the warnings are being generated? Is this a bug? Have I done something wrong?

Hello all,

First post. Thank you for these amazing tools. I have spent two days pulling my hair out, trying all enumerations, searching the documentation and forums, and in the end I come to you for help. Please forgive me if these topics have been covered elsewhere.

I have several VCFs generated by SomaticSniper that I'd like to filter based on the SomaticScore (SSC in the FORMAT field). I was working with VariantFiltration and SelectVariants, and trying to use different options, as well as regular expressions, to select those calls with a SSC over 40. I have been unable to do so. I also looked into trying to figure out JEXL, and using the last command listed on the documentation page, about using the VariantContext feature to drill into an array. I cannot get it to recognize the SSC column of the FORMAT field and then filter for the TUMOR sample.

Using VariantFiltration I was using -select (but I understand now that this searches the INFO field only). I was then using the --genotypeFilterExpression, but it would not add the FT tag to the FORMAT field as it said it would, it would just apply PASS to everything.

java -Xmx4-jar GenomeAnalysisTK.jar -T VariantFiltration -R ~/Documents/reference/human_g1k_v37.fasta -V '/home/registry3/Desktop/merged/104024sniperRAWSNPS.vcf' --G_filter "SSC < 40.0" --G_filterName "myFilter" -o '/home/registry3/Desktop/merged/104024sniperFILTEREDSNPS.vcf'

Using SelectVariants, I was using -sn to select the TUMOR sample and then using -select_expressions, but I guess this also only works on the INFO field. I had been trying to use --sample_expression which gives the ability to use a regular expression, but then I never had good results; it wouldn't do any filtering, and output the entire input file. Does the regular expression only apply to the sample name, and not the content of each line? Trying to select SSC over 40 from a line like this

#CHROM   POS ID  REF ALT QUAL    FILTER  INFO    FORMAT  TUMOR
1   10177   0   A   C   0   0   AC=1;AF=0.500;AN=2;DP=62    GT:AMQ:BCOUNT:BQ:DP:DP4:GQ:IGT:MQ:SS:SSC:VAQ    0/1:16,15:40,22,0,0:28,25:62:31,9,10,12:37:0/1:16:2:19:37

I used a line such as this, to look at the second to last number in the FORMAT field based on : dividers

java -Xmx4-jar GenomeAnalysisTK.jar -R ~/Documents/reference/human_g1k_v37.fasta -T SelectVariants --variant '/home/registry3/Desktop/merged/104024sniperSNPs.vcf' -o '/home/registry3/Desktop/merged/104024sniperSSC40.vcf' -se ".*:[4,5,6,7,8,9][1,2,3,4,5,6,7,8,9]:[1234567890]{2,3}\$"

I am not a coder, as you can probably see, but I'm trying to get this worked out. This output the entire file still, with SSC values above and below 40.

Looking into use the vc.getGenotype array access, I could not find much documentation about VariantContext; I was looking through the files on github, looking through the code and looking for samples, since the .getAD() from the documentation seems to work, but alas, there is no .getSCC() available. Is using vc. the best way to drill into an array (the FORMAT field) and search for what I want?

I didn't post all the code and output, trying to keep this as short as possible. I can post pastebin outputs if that would be helpful. Thank you, David