Dear all, thank you for your hints. I would prefer to do not use Rserve as Dirk mentioned.
@Simon I have full control over the Java implementation - I can adapt the code that I use for the communication R <-> Java. > You can natively access structures on each side. The fastest way is to > use R representation (column-oriented) in Java - that is much faster > than any kind of serialization or anything you mention above since you > pass the variables as a whole. Could you please send any reference to more examples or documentation that can help me? The main goal is to copy a full dataframe from R to Java. Best regards, Jaroslav On 2015-12-07 03:19, Simon Urbanek wrote: > On Dec 6, 2015, at 12:36 PM, Ing. Jaroslav Kuchař > <jaroslav.kuc...@fit.cvut.cz> wrote: > >> Dear all, >> >> in our ongoing project we use Java implementations of several >> algorithms. We also provide a “wrapper” implemented as an R package >> using rJava (https://github.com/jaroslav-kuchar/rCBA). Based on our >> recent experiments, the significant portion of time is spent on copying >> a dataframe from R to Java. The Java implementation needs access to the >> source dataframe. >> >> I have tested several approaches: calling Java method row-by-row; >> serialize the whole data-frame to a temp file and parsing in Java; or >> row binding to a single vector and calling a single Java method. Each >> approach has its limitations e.g. time-consuming row-by-row copying, >> serialization and parsing performance or memory limitations of a single >> vector. >> >> Is there an efficient approach how to copy a dataframe from R to Java >> and another one from Java to R? >> >> Thanks for any help you can provide... >> > > You can natively access structures on each side. The fastest way is to > use R representation (column-oriented) in Java - that is much faster > than any kind of serialization or anything you mention above since you > pass the variables as a whole. > > Typically, the bottleneck are Java applications which may require very > inefficient data structures. If you have control over the algorithms, > you can simply use proper data structures and avoid that problem. If > you don't have control, you'll have to add Java code that converts to > whatever structure is needed by the Java code form the data frame > pushed to the Java side. The main point here is that you do NOT want > to do any conversion on the R side. > > Cheers, > Šimon ______________________________________________ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel
