Package: bit
Type: Package
Title: A class for vectors of 1-bit booleans
Version: 1.0-2
Date: 2009-02-13
Author: Jens Oehlschl�gel
Maintainer: Jens Oehlschl�gel <oehl_list@gmx.de>
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%.
License: GPL-2
LazyLoad: yes
Encoding: latin1
Packaged: 2009-04-13 14:22:17 UTC; Jens Oehlschlaegel
Repository: CRAN
Date/Publication: 2009-04-15 07:33:07

Package: bit
Type: Package
Title: A class for vectors of 1-bit booleans
Version: 1.0
Date: 2008-09-29
Author: Jens Oehlschl�gel <Jens.Oehlschlaegel@truecluster.com>
Maintainer: Jens Oehlschl�gel <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%.
License: GPL-2
LazyLoad: yes
Encoding: latin1
Packaged: Wed Oct  8 20:20:10 2008; Jens Oehlschlaegel