Add the -A flag to sourmash sig subtract to allow for signature subtraction from signatures with abundance tracking

[taylorreiter]

I just tried to subtract a signature (a set of core genes) from another signature (a transcriptome), with the goal of getting track abund hashes from all expressed genes that were not in the core genome. I got the error, Cannot use subtract on signatures with abundance tracking, sorry! Would it be possible to add an -A flag like sourmash sig intersect has, so I could choose which signature to inherit abundances from??

[ctb]

yep - you want to subtract the hashes in a boolean fashion (present/not present), and then inherit the abundances on remaining hashes?

[taylorreiter]

yes exactly!

[ctb]

working on it over here: #1889.

I have a bit more to do to round out the PR, but the current code should work. Also see the new sourmash sig inflate 😁