On 11/04/2012 20:36, Matthew Dowle wrote:
In DESCRIPTION if I set LazyLoad to 'yes' will data.table (for example) then be byte compiled for users who install the binary package from CRAN on Windows?
No. LazyLoad is distinct from byte compilation. All installed packages use lazy loading these days (for simplicity: a very few do not benefit from it as they use all their objects at startup).
This question is based on reading section 1.2 of this document : http://www.divms.uiowa.edu/~luke/R/compiler/compiler.pdf I've searched r-devel and Stack Overflow history and have found questions and answers relating to R CMD INSTALL and install.packages() from source, but no answer (as yet) about why binary packages for Windows appear not to be byte compiled. If so, is there any reason why all packages should not set LazyLoad to 'yes'. And if not, could LazyLoad be 'yes' by default?
I wonder why you are not reading R's own documentation. 'Writing R Extensions' says
'The `LazyData' logical field controls whether the R datasets use lazy-loading. A `LazyLoad' field was used in versions prior to 2.14.0, but now is ignored.
The `ByteCompile' logical field controls if the package code is byte-compiled on installation: the default is currently not to, so this may be useful for a package known to benefit particularly from byte-compilation (which can take quite a long time and increases the installed size of the package).'
Note that the majority of CRAN packages benefit very little from byte-compilation because almost all the time of their computations is spent in compiled code. And the increased size also may matter when the code is loaded into R.
Thanks, Matthew ______________________________________________ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel
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