[Cbc] Compiling CLP/CBC with UFL AMD support

[Stefan Vigerske]

Hi,

> I have just downloaded from SVN the latest CBC/CLP source for the trunk 
> branch. I then tried to modify Clp/src/Makefile.in, so that I can build 
> CLP/CBC with UFL AMD support, so that the Barrier method runs at a 
> reasonable speed.
> 
> I have been doing this for several years now, and the last time I did 
> this was in October last year, but it seems something have changed since 
> then --
> 
> I used to add the linking of the libamd.a library to ADDLIBS in 
> Makefile.in, but ADDLIBS is no longer there. Can anyone suggest where I 
> need to add the library for linking?

You could specify additional linker flags via the LDFLAGS variable at
the configure call, e.g., ./configure LDFLAGS=-lamd
But I don't see how this could be sufficient to let Clp know that it
should use this library. Maybe you also need to set ADD_CXXFLAGS to do
something -DCLP_USE_CHOLMOD or so.

If you prefer changing Makefile.in, then modify the CLPLIB_LIBS variable.

> It would be nice if linking of UFL AMD can be done without modifying the 
> source -- this used to be possible. Is there any plans to do this again?

Best would be to have a configure option
(--with-uflamd-{libs,incdir}...), you could create a Clp ticket for
this, https://projects.coin-or.org/Clp/newticket

> A related question is if using UFL AMD is still needed -- I remember 
> reading that the native ordering for CLP have been greatly improved,
> and in October last year I did try compiling CBC/CLP without UFL AMD, 
> and trying the Barrier method, but it still seem to be 10-100 times 
> slower than with UFL AMD. Was this because I should have included some 
> option when configuring, or is it because I am using the trunk branch?
> 
> Is there a big performance difference between the trunk and the stable 
> branch? I am using the trunk branch because I need some functionality 
> that John added to the trunk branch some years ago.

Things that have been added to Clp years ago should be in various
stable's by now.
E.g., try Clp 1.12, this one did not have the changes to the buildsystem
in it yet, and was created from Clp trunk rev1555 9 months ago.

Stefan

> 
> Thanks in advance for any help/information!
> 
> Kish
> 
> 
> 


-- 
Stefan Vigerske
Humboldt University Berlin, Numerical Mathematics
http://www.math.hu-berlin.de/~stefan