[R] RWeka and multicore package

CEO'Riley ceoriley at gmail.com
Thu Oct 17 19:28:00 CEST 2013

I received the following error message with the multicore package:

Warning in install.packages :
  package ‘multicore’ is not available (for R version 3.0.2)
Warning in install.packages :
  package ‘multicore’ is not available (for R version 3.0.2)
Warning message:
package ‘multicore’ is not available (for R version 3.0.2)

With gratitude,
CEO'Riley Jr.
Charles Ellis O'Riley Jr.

Ambition is a state of permanent dissatisfaction with the present

-----Original Message-----
From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-project.org] On
Behalf Of Luís Paulo F. Garcia
Sent: Thursday, October 17, 2013 12:22 PM
To: r-help at r-project.org
Subject: [R] RWeka and multicore package

I work very mutch with the packages RWeka and multicore. If you try to run
J48 or any tree of RWeka with multicore we hava some errors.

Example I:


mclapply(1:100, function(i) {
    J48(Species ~., iris);

Output:  "Error in .jcall(o, \"Ljava/lang/Class;\", \"getClass\") : \n
java.lang.ClassFormatError: Incompatible magic value 1347093252 in class
file java/lang/ProcessEnvironment$StringEnvironment\n"

Example II:


mclapply(1:100, function(i) {
    RWeka::J48(Species ~., iris);

Output: Erro em .jcall(x$classifier, "S", "toString") :
  RcallMethod: attempt to call a method of a NULL object.

Do you know some way to work with parallel processing and RWeka? I tried MPI
and SNOW without success.

R version 3.0.2 (2013-09-25) -- "Frisbee Sailing"
Ubuntu 12.04 x64

Lums Paulo Faina Garcia
Engenheiro de Computagco - Universidade de Sco Paulo Sco Carlos - SP -

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