GATK 3.1 was released on March 18, 2014. Highlights are listed below. Read the detailed version history overview here: http://www.broadinstitute.org/gatk/guide/version-history
--pair_hmm_implementation VECTOR_LOGLESS_CACHING. Please see the 3.1 Version Highlights for more details about expected speed ups and some background on the collaboration that made these possible.
When I use SelectVariants -fraction option more than once, I always get the same variant sites. The same happens for RandomlySplitVariants. Is there a way of randomly taking a fraction of the vcf that is not always the same, but truly random (which means it will pick different sites each time, of course with a certain probability of including common sites)?