bit v1.1-14

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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).

Functions in bit

Name Description
c.bit Concatenating bit and bitwhich vectors
unattr Attribute removal
vecseq Vectorized Sequences
setattributes Attribute setting by reference
rlepack Hybrid Index, rle-pack utilities
regtest.bit Regressiontests for bit
repeat.time Adaptive timer
repfromto Virtual recycling
ri Range index
as.which Coercion to (positive) integer positions
Extract Extract or replace part of an bit vector
Summary Summaries of bit vectors
as.bit Coercing to bit
bbatch Balanced Batch sizes
bit_init Initializing bit masks
as.logical.bit Coercion from bit, bitwhich and ri to logical, integer, double
as.bitwhich Coercing to bitwhich
physical Physical and virtual attributes
bit-package A class for vectors of 1-bit booleans
is.bit Testing for bit, bitwhich and ri selection classes
clone Cloning ff and ram objects
chunk Chunked range index
intrle Hybrid Index, C-coded utilities
ramsort Generics for in-RAM sorting and ordering
LogicBit Boolean operators and functions for class bit
is.sorted Generics related to cache access
length.bit Getting and setting length of bit, bitwhich and ri objects
bitwhich A class for vectors representing asymetric selections
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Details

Type Package
Date 2018-04-11
License GPL-2
LazyLoad yes
ByteCompile yes
Encoding UTF-8
URL http://ff.r-forge.r-project.org/
NeedsCompilation yes
Packaged 2018-05-27 20:28:22 UTC; jens
Repository CRAN
Date/Publication 2018-05-29 16:56:33 UTC
depends R (>= 2.9.2)
Contributors Jens Oehlschl�gel

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