Re: [Rd] Save and serialize
On Mon, 7 Feb 2011, Hadley Wickham wrote: Hi all, Is there any relationship between save and serialize? Do they use the same algorithm? See the R-internals manual: there is more info in the R-devel version, not least because saveRDS() is added to the mix. But basically serialize() and saveRDS() use the same format, and save() writes a header and then serializes a pairlist of the objects given. 'The same algorithm' is somewhat misleading here: strictly no, as they manage to use four entry points to the code base. Hadley -- Assistant Professor / Dobelman Family Junior Chair Department of Statistics / Rice University http://had.co.nz/ __ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel -- Brian D. Ripley, rip...@stats.ox.ac.uk Professor of Applied Statistics, http://www.stats.ox.ac.uk/~ripley/ University of Oxford, Tel: +44 1865 272861 (self) 1 South Parks Road, +44 1865 272866 (PA) Oxford OX1 3TG, UKFax: +44 1865 272595 __ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel
Re: [Rd] Save and serialize
Also, if it it adds any value to what you are looking for, the output of serialize() also has header information, cf. R-devel thread 'Small inconsistency in serialize() between R versions and implications on digest()' started March 7, 2007: http://www.mail-archive.com/r-devel@r-project.org/msg07931.html It caused us some headaches when trying to generate identical output of the same input using different versions of R. It was solved in that thread. See code for digest::digest() on how to skip/ignore that header. /Henrik On Mon, Feb 7, 2011 at 1:51 PM, Prof Brian Ripley rip...@stats.ox.ac.uk wrote: On Mon, 7 Feb 2011, Hadley Wickham wrote: Hi all, Is there any relationship between save and serialize? Do they use the same algorithm? See the R-internals manual: there is more info in the R-devel version, not least because saveRDS() is added to the mix. But basically serialize() and saveRDS() use the same format, and save() writes a header and then serializes a pairlist of the objects given. 'The same algorithm' is somewhat misleading here: strictly no, as they manage to use four entry points to the code base. Hadley -- Assistant Professor / Dobelman Family Junior Chair Department of Statistics / Rice University http://had.co.nz/ __ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel -- Brian D. Ripley, rip...@stats.ox.ac.uk Professor of Applied Statistics, http://www.stats.ox.ac.uk/~ripley/ University of Oxford, Tel: +44 1865 272861 (self) 1 South Parks Road, +44 1865 272866 (PA) Oxford OX1 3TG, UK Fax: +44 1865 272595 __ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel __ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel
Re: [Rd] Save and serialize
Thanks to you both for the information - that's exactly the level of detail I was looking for. I ask because I want to play around with a function to automatically cache expensive operations to disk, in a way that can be lazy loaded on the next run. Hadley On Mon, Feb 7, 2011 at 4:06 PM, Henrik Bengtsson h...@biostat.ucsf.edu wrote: Also, if it it adds any value to what you are looking for, the output of serialize() also has header information, cf. R-devel thread 'Small inconsistency in serialize() between R versions and implications on digest()' started March 7, 2007: http://www.mail-archive.com/r-devel@r-project.org/msg07931.html It caused us some headaches when trying to generate identical output of the same input using different versions of R. It was solved in that thread. See code for digest::digest() on how to skip/ignore that header. /Henrik On Mon, Feb 7, 2011 at 1:51 PM, Prof Brian Ripley rip...@stats.ox.ac.uk wrote: On Mon, 7 Feb 2011, Hadley Wickham wrote: Hi all, Is there any relationship between save and serialize? Do they use the same algorithm? See the R-internals manual: there is more info in the R-devel version, not least because saveRDS() is added to the mix. But basically serialize() and saveRDS() use the same format, and save() writes a header and then serializes a pairlist of the objects given. 'The same algorithm' is somewhat misleading here: strictly no, as they manage to use four entry points to the code base. Hadley -- Assistant Professor / Dobelman Family Junior Chair Department of Statistics / Rice University http://had.co.nz/ __ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel -- Brian D. Ripley, rip...@stats.ox.ac.uk Professor of Applied Statistics, http://www.stats.ox.ac.uk/~ripley/ University of Oxford, Tel: +44 1865 272861 (self) 1 South Parks Road, +44 1865 272866 (PA) Oxford OX1 3TG, UK Fax: +44 1865 272595 __ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel -- Assistant Professor / Dobelman Family Junior Chair Department of Statistics / Rice University http://had.co.nz/ __ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel
Re: [Rd] Save and serialize
On Mon, Feb 7, 2011 at 3:15 PM, Hadley Wickham had...@rice.edu wrote: Thanks to you both for the information - that's exactly the level of detail I was looking for. I ask because I want to play around with a function to automatically cache expensive operations to disk, in a way that can be lazy loaded on the next run. So starting with digest v0.3.0 (April 2007), the digest() method can be considered consistent across R version (in addition to across R sessions). FYI, recently in R-devel serialize(), which digest() relies on, gained a 'version' argument reserved for future usage. From NEWS: - serialize() and unserialize() are no longer described as ‘experimental’. The interface is now regarded as stable, although the serialization format may well change in future releases. (serialize() has a new argument version which would allow the current format to be written if that happens.) I've tested, and the introduction of this argument was done such that the serialized object is identical to as before (R = 2.12.x). Thus, digest() will generate the same output also in R v2.13.0. At some point, we will add an option to digest() for specifying what 'version' value should be passed to serialize(), but it doesn't sound like it is too urgent to add that. Any updates to digest() will also be backward compatible, so as long as you use digest() you shouldn't have to worry about consistency. /Henrik Hadley On Mon, Feb 7, 2011 at 4:06 PM, Henrik Bengtsson h...@biostat.ucsf.edu wrote: Also, if it it adds any value to what you are looking for, the output of serialize() also has header information, cf. R-devel thread 'Small inconsistency in serialize() between R versions and implications on digest()' started March 7, 2007: http://www.mail-archive.com/r-devel@r-project.org/msg07931.html It caused us some headaches when trying to generate identical output of the same input using different versions of R. It was solved in that thread. See code for digest::digest() on how to skip/ignore that header. /Henrik On Mon, Feb 7, 2011 at 1:51 PM, Prof Brian Ripley rip...@stats.ox.ac.uk wrote: On Mon, 7 Feb 2011, Hadley Wickham wrote: Hi all, Is there any relationship between save and serialize? Do they use the same algorithm? See the R-internals manual: there is more info in the R-devel version, not least because saveRDS() is added to the mix. But basically serialize() and saveRDS() use the same format, and save() writes a header and then serializes a pairlist of the objects given. 'The same algorithm' is somewhat misleading here: strictly no, as they manage to use four entry points to the code base. Hadley -- Assistant Professor / Dobelman Family Junior Chair Department of Statistics / Rice University http://had.co.nz/ __ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel -- Brian D. Ripley, rip...@stats.ox.ac.uk Professor of Applied Statistics, http://www.stats.ox.ac.uk/~ripley/ University of Oxford, Tel: +44 1865 272861 (self) 1 South Parks Road, +44 1865 272866 (PA) Oxford OX1 3TG, UK Fax: +44 1865 272595 __ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel -- Assistant Professor / Dobelman Family Junior Chair Department of Statistics / Rice University http://had.co.nz/ __ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel __ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel
