[Rd] Using SQLBulkOperations in RODBC

I have a question for the R core development team: Are there any near-term plans to incorporate the ODBC API function SQLBulkOperations into the RODBC package? As you are probably well aware, the sqlSave() function uses a row-by-row insert (even in the 'fast' version) that imposes heavy DB transac

[Rd] Creating model frame from R formula inside compiled code

I am developing a custom regression package, which accepts a formula object as way of setting up the model matrix and response variable from a data frame. For large data sets, I expect that going through R memory might be too slow, so I'm thinking about reading the data directly into C (e.g. from a

[Rd] How to call an MPI-enabled program from R?

Conceptually, how is it possible to call an MPI-parallelized code in C from R? My experience with MPI so far indicates that one has to launch an MPI-enabled binary using a command like mpiexec -n In other words, I'm not sure how to create an MPI 'library' and then call it from a single-threaded

Re: [Rd] Is it possible to pass a function argument from R to compiled code in C?

OK, thanks. But there are two issues with using ".Call": 1- I may give up performance if I am literally running R code inside C, right? In some ways, wouldn't it defy the purpose of calling a compiled code if I end up back in R? 2- If I use the ".Call" interface, the resulting code will be tailor

[Rd] Is it possible to pass a function argument from R to compiled code in C?

C implementation, but I imagine it's going to be nearly impossible to pass a function from R to C. Are there any exact or approximate solutions available? Thank you, Alireza Mahani -- View this message in context: http://r.789695.n4.nabble.com/Is-it-possible-to-pass-a-function-argument-

Re: [Rd] How to safely using OpenMP pragma inside a .C() function?

I have no R API calls inside the parallelized block. I will work on creating a self-contained example and post it for your review. Thanks! -Alireza -- View this message in context: http://r.789695.n4.nabble.com/How-to-safely-use-OpenMP-pragma-inside-a-C-function-tp3777036p3778482.html Sent from t

[Rd] How to safely using OpenMP pragma inside a .C() function?

tion, and if yes how? Thank you, Alireza Mahani -- View this message in context: http://r.789695.n4.nabble.com/How-to-safely-using-OpenMP-pragma-inside-a-C-function-tp3777036p3777036.html Sent from the R devel mailing list archive at Nabble.com. __ R

Re: [Rd] Best practices for writing R functions

The fact that R doesn't automatically copy the function argument is very useful when you mainly want to pass arguments to another function. Thanks to all of you for mentioning this! Another trick to reduce verbosity of code (and focus on algorithm logic rather than boilerplate code) is to maintain

[Rd] Best practices for writing R functions

I am developing an R package for internal use, and eventually for public release. My understanding is that there is no easy way to avoid copying function arguments in R (i.e. we don't have the concept of pointers in R), which makes me wary of freely creating chains of function calls since each func

Re: [Rd] Performance of .C and .Call functions vs. native R code

Prof. Bates, It looks like you read my mind! I am working on writing an R package for high-performance MCMC estimation of a class of Hierarchical Bayesian models most often used in the field of quantitative marketing. This would essentially be a parallelized version of Peter Rossi's bayesm package

[Rd] Measuring and comparing .C and .Call overhead

Further pursuing my curiosity to measure the efficiency of R/C++ interface, I conducted a simple matrix-vector multiplication test using .C and .Call functions in R. In each case, I measured the execution time in R, as well as inside the C++ function. Subtracting the two, I came up with a measure o

Re: [Rd] Manipulating single-precision (float) arrays in .Call functions

Simon, Thank you for elaborating on the limitations of R in handling float types. I think I'm pretty much there with you. As for the insufficiency of single-precision math (and hence limitations of GPU), my personal take so far has been that double-precision becomes crucial when some sort of erro

Re: [Rd] Manipulating single-precision (float) arrays in .Call functions

Duncan, Thank you for your reply. This is a rather unfortunate limitation, because for large data sizes there is a significant difference between the performance of '.C' and '.Call'. I will have to do some tests to see what sort of penalty I incur for copying from double to float inside my C++ cod

[Rd] Manipulating single-precision (float) arrays in .Call functions

I am writing a wrapper function in C++ that calls a GPU kernel. My array type for the GPU kernel is float, so I would like my wrapper function to receive float arrays from R. I understand that I can use 'as.single' in R to copy a double-precision vector from R in single-precision format while using

Re: [Rd] Performance of .C and .Call functions vs. native R code

You are absolutely right Gabe! I removed the line 'dim(A) <- dim(A)[1] * dim(A)[2]' and my code still executes properly. As you said, matrices are internally stored as one-dimensional arrays (column-major by default), it's just that R exposes them differently by assigning different attributes to th

Re: [Rd] Performance of .C and .Call functions vs. native R code

(I am using a LINUX machine) Jeff, In creating reproducible results, I 'partially' answered my question. I have attached two scripts, 'mvMultiply.r' and 'mvMultiply.cc'. Please copy both files into your chosen directory, then run 'Rscript mvMultiply.r' in that directory while changing the two boo