[Cbc] Poor performance on windows

[Haroldo Santos]

Hi,

Do you use additional compilation flags ?
Recent GCC versions support Link Time Optimization, which usually provides
a good speedup, just call, before calling configure:

export CXXFLAGS="-Ofast -flto"
export LDFLAGS="-Ofast -flto"
export CFLAGS="-Ofast -flto"

It is also recommended to include Blas and Lapack (speed up some operations
on dense matrixes). (download with ./get.Lapack and ./get.Blas in their
respective ThirdParty directories (gfortran must be installed on linux and
mingw).

If lapack and blas are included, compilation flags would be:
export FCFLAGS="-Ofast -flto"
export F77FLAGS="-Ofast -flto"


Cheers,

Haroldo





On Mon, Jan 29, 2018 at 6:02 PM, Alpár Jüttner <alpar at cs.elte.hu> wrote:

> Hi,
>
> We develop an optimization algorithm which calls CBC to solve a number of
> small to medium size MIP problems. It works fine on Linux, but the
> execution time increases - sometimes dramatically - on Windows.
>
> Could anyone give me some hints on the possible reasons for that and how
> to overcome?
>
> Some details:
> The code is written in C++, and we build up and solve the MIP problems
> directly with the CBC API.
> We compile CBC from source with this configuration:
>
> ./configure --enable-static --disable-shared --disable-cbc-parallel
>
> On Windows, we tried Cygwin and MinGW.
>
> With Cygwin, both CBC and our code is compiled in Windows, in the cygwin
> shell just the same way as in linux.
>
> With MinGW, we do cross compiling on linux. The CBC source is configured
> as:
>
> ./configure --host=x86_64-w64-mingw32 --enable-static --disable-shared
> --disable-cbc-parallel
>
> Using MinGW we get a faster executable, but still slower than the linux
> version by a magnitude.
>
> We tried both the trunk version and release 2.9.9. There is no significant
> difference.
>
> Many thanks in advance for any help!
>
> Regards,
> Alpár
>
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>
>


-- 
=============================================================
Haroldo Gambini Santos
Computing Department
Universidade Federal de Ouro Preto - UFOP
email: haroldo [at ] iceb.ufop.br
home/research page: www.decom.ufop.br/haroldo


It has long been an axiom of mine that the little things are infinitely
the most important.
-- Sir Arthur Conan Doyle, "A Case of Identity"
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