[R-sig-hpc] multicore mclapply hangs when 'debug' loaded

Dirk Eddelbuettel edd at debian.org
Mon Aug 10 19:00:36 CEST 2009

On 10 August 2009 at 15:15, Rune Schjellerup Philosof wrote:
| Dirk Eddelbuettel skrev:
| > On 10 August 2009 at 13:55, Rune Schjellerup Philosof wrote:
| > | When I execute mclapply it creates the needed processes, but these
| > | processes never begin computing anything, they just wait indefinitely.
| >   
| I discovered that it occurs when I have loaded the 'debug' package at
| the same time as the 'multicore' package.
| However, I use a version of the 'debug' package that hasn't been
| released yet.
| Still though, it also some times happen when I don't have 'debug' loaded
| (I just realized because of the sessionInfo included below).
| But at the moment I have to load the 'debug' package to make the bug
| appear (just loading mvbutils does not cause the effect).
| > Would you have a reproducible example?  
| >   
| Start R --vanilla:
| library(debug)
| library(multicore)
| example(mclapply)

How about the good old

  Patient:  "Doctor, doctor, it hurts when I do this."  
  Doctor:   "Well then don't do it."

You seem to have identified that the debug package interferes with operation
of the multicore package.  I suggest that you contact the author of debug (as
you already did per CC) and try to work out a solution with him. In the
meantime, just don't load it when you run multicore.

PS Mark: r-sig-hpc is subscriber-only, you may get bounces on follow-ups.

Three out of two people have difficulties with fractions.

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