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Jellyfish

Counting k-mers in DNA

https://github.com/gmarcais/Jellyfish

A k-mer is a substring of length k, and counting the occurrences of all such substrings is a central step in many analyses of DNA sequence. JELLYFISH can count k-mers using an order of magnitude less memory and an order of magnitude faster than other k-mer counting packages by using an efficient encoding of a hash table and by exploiting the "compare-and-swap" CPU instruction to increase parallelism.

The module parses only *_jf.hist files. The general usage of jellyfish to be parsed by MultiQC module needs to be:

  • gunzip -c file.fastq.gz | jellyfish count -o file.jf -m ...
  • jellyfish histo -o file_jf.hist -f file.jf

In case a user wants to customise the matching pattern for jellyfish, then multiqc can be run with the option --cl-config "sp: { jellyfish: { fn: 'PATTERN' } }" where PATTERN is the pattern to be matched. For example:

multiqc . --cl-config "sp: { jellyfish: { fn: '*.hist' } }"

File search patterns​

jellyfish:
  fn: "*_jf.hist"