bit: A Class for Vectors of 1-Bit Booleans

True boolean datatype (no NAs), coercion from and to logicals, integers and integer subscripts; fast boolean operators and fast summary statistics. With 'bit' vectors you can store true binary booleans {FALSE,TRUE} at the expense of 1 bit only, on a 32 bit architecture this means factor 32 less RAM and ~ factor 32 more speed on boolean operations. Due to overhead of R calls, actual speed gain depends on the size of the vector: expect gains for vectors of size > 10000 elements. Even for one-time boolean operations it can pay-off to convert to bit, the pay-off is obvious, when such components are used more than once. Reading from and writing to bit is approximately as fast as accessing standard logicals - mostly due to R's time for memory allocation. The package allows to work with pre-allocated memory for return values by calling .Call() directly: when evaluating the speed of C-access with pre-allocated vector memory, coping from bit to logical requires only 70% of the time for copying from logical to logical; and copying from logical to bit comes at a performance penalty of 150%. the package now contains further classes for representing logical selections: 'bitwhich' for very skewed selections and 'ri' for selecting ranges of values for chunked processing. All three index classes can be used for subsetting 'ff' objects (ff-2.1-0 and higher).

AuthorJens Oehlschlgel <Jens.Oehlschlaegel@truecluster.com>
Date of publication2015-06-26 17:46:09
MaintainerJens Oehlschlgel <Jens.Oehlschlaegel@truecluster.com>
LicenseGPL-2
Version1.1-13
http://ff.r-forge.r-project.org/

View on R-Forge

Functions

Files

DESCRIPTION
NAMESPACE
NEWS
R
R/attrutil.R R/bit.R R/chunkutil.R R/clone.R R/generics.R R/rle.R R/timeutil.R R/zzz.R
exec
exec/make_rd.pl
exec/prebuild.sh
inst
inst/ANNOUNCEMENT-1.0.txt
inst/README_devel.txt
man
man/Extract.rd
man/LogicBit.rd
man/Summary.rd
man/as.bit.rd
man/as.bitwhich.rd
man/as.logical.bit.rd
man/as.which.rd
man/bbatch.rd
man/bit-package.rd
man/bit_init.rd
man/bitwhich.rd
man/c.bit.rd
man/chunk.rd
man/clone.rd
man/intrle.rd
man/is.bit.rd
man/is.sorted.rd
man/length.bit.rd
man/physical.rd
man/ramsort.rd
man/regtest.bit.rd
man/repeat.time.rd
man/repfromto.rd
man/ri.rd
man/rlepack.rd
man/setattributes.rd
man/unattr.rd
man/vecseq.rd
src
src/attrutil.c
src/bit.c
src/chunkutil.c
src/clone.c
src/rle.c

Questions? Problems? Suggestions? or email at ian@mutexlabs.com.

Please suggest features or report bugs with the GitHub issue tracker.

All documentation is copyright its authors; we didn't write any of that.