ctsa/hap-eval

A VCF comparison engine for structual variant benchmarking

Hap-Eval

An open-source VCF comparison engine for structural variant benchmarking

Note: hap-eval is pre-release software and is under active development. If hap-eval does not work with your VCF, please file an issue

Installation

You can use the following commands to clone the repository and vcflib submodule to your machine and install the tool.

git clone --recurse-submodules https://github.com/Sentieon/hap-eval.git
pip install ./hap-eval

Usage

usage: hap_eval [-h] -r FASTA -b VCF -c VCF [-i BED] [-t INT] [--base_out VCF]
                [--comp_out VCF] [--maxdist INT] [--minsize INT]
                [--maxdiff FLOAT] [--metric STR]

optional arguments:
  -h, --help            show this help message and exit
  -r FASTA, --reference FASTA
                        Reference file
  -b VCF, --base VCF    Baseline vcf file
  -c VCF, --comp VCF    Comparison vcf file
  -i BED, --interval BED
                        Evaluation region file
  -t INT, --thread_count INT
                        Number of threads
  --base_out VCF        Annotated baseline vcf file
  --comp_out VCF        Annotated comparison vcf file
  --maxdist INT         Maximum distance to cluster variants (default: 1000)
  --minsize INT         Minimum size of variants to consider (default: 50)
  --maxdiff FLOAT       Haplotype difference threshold (default: 0.2)
  --metric STR          Distance metric (default: Levenshtein)

Interpreting the output

Upon successful evaluation, hap-eval will print output similar to the following:

Counter({'MM': 9413, 'FP': 280, 'FN': 183, 'MX': 58, 'XX': 18, '??': 9})
precision 0.9627 recall 0.9723 f1 0.9675

The Counter contains the number of regions evaluated along with evaluation result.

• MM - A true-positive. The two haplotypes in the query match the two haplotypes in the truth VCF. There is at least one variant in both VCFs.
• FN - A simple false-negative. There is an event in the truth but no corresponding event in the query in the nearby region.
• FP - A simple false-positive. There is an event in the query but no corresponding event in the truth in the nearby region.
• ?? - The region cannot be evaluated. This is likely due to the large number of potential haplotypes at the region.
• MX and XX - both the truth and the query have some type of event, but the difference between at least one of the best assembled haplotype pairs is greater than --maxdiff.
  • XX - both of the best assembled haplotypes in the query have a difference greater than --maxdiff from the truth.
  • MX - one of the best assembled haplotypes in the query has a distance greater than --maxdiff from the truth. The other has a difference less than --maxdiff (considered a match).

hap-eval will use the evaluation counts to output a global evaluation on the matching between the query and truth VCFs using the following formula:

tp = float(summary['MM'])
ff = summary['MX'] + summary['XX'] + summary['??']
fp = summary['FP'] + ff
fn = summary['FN'] + ff

if tp < 1:
  print('precision 0.0 recall 0.0 f1 0.0')
  return 0
print('precision %.4f recall %.4f f1 %.4f' %
  (tp/(tp+fp), tp/(tp+fn), tp/(tp+(fp+fn)/2)))

??, MX, and XX events are reported as a combined FP/FN due to the presence of variants in both the truth and query VCFs at the evaluated region.