[R] possible bug in function 'mclapply' of package parallel

Michael Weylandt michael.weylandt at gmail.com
Thu Dec 13 10:50:34 CET 2012


Mailing list ate the attachment. 

Can you send it plain text (if short) or post it somewhere online?

Michael

On Dec 13, 2012, at 1:54 AM, Asis Hallab <asis.hallab at gmail.com> wrote:

> Dear parallel users and developers,
> 
> I might have encountered a bug in the function 'mclapply' of package
> 'parallel'. I construct a matrix using the same input data and code with a
> single difference: Once I use mclapply and the other time lapply.
> 
> Shockingly the result is NOT the same.
> 
> To evaluate please unpack the attached archive and execute
> Rscript mclapply_test.R
> 
> I put the two simple functions I wrote inside the R script and the
> serialized input matrix.
> My function is once executed using mclapply and the other time lapply
> internally. - There's an argument lapply.funk, one can set to mclapply.
> 
> The results are checked for identity with a striking FALSE.
> 
> Any hints on my misuse and or misunderstanding of mclapply or verification
> of a true bug will be much appreciated.
> 
> Kind regards!
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