Correction to: Nature Methods https://doi.org/10.1038/s41592-018-0171-3, published online 30 October 2018

The version of this paper originally published cited a preprint version of ref. 12 instead of the published version (Proc. Natl. Acad. Sci. USA 115, 5594–5599; 2018), which was available before this Nature Methods paper went to press. The reference information has been updated in the PDF and HTML versions of the article.