From: Rudi Cilibrasi <cilibrar@...>
Date: 2007-10-04T06:53:18+09:00
Subject: problem with OpenMP in Ruby extension

Hi everybody,

I am the main developer of CompLearn, an open-source machine learning library
for scientific researchers.  I have written a Ruby binding for CompLearn
called complearn-ruby.  It has worked fine in the past.  But it has a problem
ever since I converted the base library (libcomplearn) to use OpenMP for
multicore processor support.  If I just try to use the simplest approach that
has worked in the past in my extconf.rb, I get the following problem when I
try to require the C-extension Ruby binding complearn4r.so and use the
multicore part of the system:

ruby: symbol lookup error: /usr/lib/libcomplearn.so.1: undefined symbol: GOMP_pa
rallel_start

To try to fix this error,

I adjusted the extconf.rb to include this line:

have_library('gomp', 'main')

And rebuilding works but running a simple test program (just trying to require
complearn) fails in a different way than before:

/home/cilibrar/rlc/projects/complearn/complearn-ruby/ext/complearn/complearn4r.s
o: libgomp.so.1: shared object cannot be dlopen()ed - /home/cilibrar/rlc/project
s/complearn/complearn-ruby/ext/complearn/complearn4r.so (LoadError)
        from /home/cilibrar/rlc/projects/complearn/complearn-ruby/lib/complearn.
rb:2
        from tests/t2.rb:1:in `require'
        from tests/t2.rb:1

I don't know what else to try and wonder if anybody else can offer a clue?

I have tried for a long time experimenting with CFLAGS, CPPFLAGS, LDFLAGS,
and -fopenmp among other settings but I still cannot seem to figure out
a solution.  I have put the source code for this problem up at

http://cilibrar.com/~cilibrar/projsup/rubbug/libcomplearn-1.0.4.tar.gz
and
http://cilibrar.com/~cilibrar/projsup/rubbug/libcomplearn-ruby-1.0.4.tar.gz

I would appreciate greatly any help anybody can offer in this problem.  Thank
you for your attention,

Rudi



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