-Switch back to the old implementation, if needed, with --use_legacy_downsampler
-LocusIteratorByStateExperimental becomes the new LocusIteratorByState, and
the original LocusIteratorByState becomes LegacyLocusIteratorByState
-Similarly, the ExperimentalReadShardBalancer becomes the new ReadShardBalancer,
with the old one renamed to LegacyReadShardBalancer
-Performance improvements: locus traversals used to be 20% slower in the new
downsampling implementation, now they are roughly the same speed.
-Tests show a very high level of concordance with UG calls from the previous
implementation, with some new calls and edge cases that still require more examination.
-With the new implementation, can now use -dcov with ReadWalkers to set a limit
on the max # of reads per alignment start position per sample. Appropriate value
for ReadWalker dcov may be in the single digits for some tools, but this too
requires more investigation.
Notify all downsamplers in our pool of the current global genomic position every
DOWNSAMPLER_POSITIONAL_UPDATE_INTERVAL position changes, not every single
positional change after that threshold is first reached.
-Off by default; engine fork isolates new code paths from old code paths,
so no integration tests change yet
-Experimental implementation is currently BROKEN due to a serious issue
involving file spans. No one can/should use the experimental features
until I've patched this issue.
-There are temporarily two independent versions of LocusIteratorByState.
Anyone changing one version should port the change to the other (if possible),
and anyone adding unit tests for one version should add the same unit tests
for the other (again, if possible). This situation will hopefully be extremely
temporary, and last only until the experimental implementation is proven.
This is in response to a request from Mauricio to make it easier
to use the downsamplers with GATKSAMRecords (as opposed to SAMRecords)
without having to do any cumbersome typecasting. Sadly, Java
language limitations make this sort of solution the best choice.
Thanks to Khalid for his feedback on this issue.
Also:
-added a unit test to verify GATKSAMRecord support with no typecasting required
-added some unit tests for the FractionalDownsampler that Mauricio will/might be using
-moved classes from private to public to better sync up with my local development
branch for engine integration
Mauricio Carneiro
David Roazen