Package: bit
Type: Package
Title: A class for vectors of 1-bit booleans
Version: 1.1.0
Date: 2009-07-07
Author: Jens Oehlschlgel <Jens.Oehlschlaegel@truecluster.com>
Maintainer: Jens Oehlschlgel <Jens.Oehlschlaegel@truecluster.com>
Description: bitmapped vectors of booleans (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. With this
        speed gain it even pays-off to convert to bit in order to avoid
        a single boolean operation on logicals or a single set
        operation on (longer) integer subscripts, the pay-off is
        dramatic 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).
License: GPL-2
LazyLoad: yes
Encoding: latin1
Packaged: 2009-07-23 20:00:38 UTC; Jens Oehlschlaegel
Repository: CRAN
Date/Publication: 2009-07-24 06:04:28
