cbc standalone binary file

[LeeU1911]

Hey there,

I tried to download packages from https://www.coin-or.org/download/binary/Cbc/?C=M;O=D but it doesn't seem to have a single cbc binary file. Instead the bin folder has cbc, clp and glpsol which are all have sizes in KB. If I run cbc <some_lp_file> from this folder, it works, but it wouldn't work if I use the cbc file alone.

We have an older version 2.9.9 of cbc standalone that is 7MB in size (didn't put in place by me) so I want to upgrade to newer version. Can you recommend a way to download the standalone cbc binary file for linux?

Thanks a lot!

[tkralphs]

Cbc can be built straightforwardly on Linux, so the best thing would be to just build your own. From the README, this will install the latest release:

wget https://raw.githubusercontent.com/coin-or/coinbrew/master/coinbrew
chmod u+x coinbrew
./coinbrew fetch Cbc@2.10.5
./coinbrew build Cbc

The second-best thing would be to install Cbc using a package manager. Instructions for that can also be found in the README.

If you really want to download binaries, that's the right place to look (for now), but you'll have to provide more information in order for us to help.

• What OS and version are you on?
• What exact file did you download?
• When you say cbc doesn't work if you use the cbc file alone, what was the error?

The reason for the difference in size of the executables is most likely that the executable you currently have is statically linked, while what you downloaded is probably linking to shared libraries and is therefore much smaller.

[LeeU1911]

Hey @tkralphs, thanks for your reply. I need a statically linked executable so I can put into my program running as serverless function on AWS Lamdba. I couldn’t use AMPL because I need version higher than 2.10.3 due to this issue. It seems to resolve in 2.10.5 and master as far as I tested with dynamically linked executable.

Everytime I try ./coinbrew build Cbc —static followed with libtool command, it gives warning as mentioned. Is there anything you can suggest for me to try differently?

Also, do you know why we stopped building statically linked executable for each release? Was hoping to find one for 2.10.5 but couldn’t find anywhere (AMPL, bintray, linux package manager, etc.)

[tkralphs]

My apologies for the confusion, it seems that the fix to our build tools mentioned in the thread referenced above, that was needed to make the static build work with stable/2.10, somehow did not make it into the 2.10.5 release, so I haven't been able to successfully make a completely static executable with that release. I was successful with the current stable/2.10 and dependencies. I will try to make a 2.10.6 with this fix, but in the meantime, I was able to get a static executable with more or less the same recipe from the thread. Here is what I did just now that worked.

~> coinbrew fetch Cbc@2.10
~> coinbrew  build Cbc --no-third-party --enable-static --disable-shared --disable-bzlib --disable-readline --disable-zlib --without-cholmod --without-lapack --without-amd LT_LDFLAGS=-all-static CXXFLAGS="-static -static-libgcc -static-libstdc++" 
~> cd dist/bin
~> ldd cbc
        not a dynamic executable

This recipe is a bit fragile and may not work universally, which is part of the reason we stopped trying to build statically with stable/2.10 (I don't know about AMPL, there is no obvious reason they haven't made a static build of 2.10.5).

Static builds with current master are much more robust and the recipe is simpler due to the use of a more recent version of the autotools. Hope this helps for now, I will update if/when there is a 2.10.6.

[LeeU1911]

Thanks @tkralphs. I finally was able to build a statically linked executable with stable/2.10 followed your commands.
Though what we wanted to upgrade was 2.10.3 where there was a good performance improvement for our use case.

I also tried on master and successful with the same recipe. Thanks a lot for your help.

Just an extra question, do you know if the performance improvements in 2.10.3 made it to current master? It seems to me that master took 10+ seconds to solve the lp mentioned here while stable/2.10 took only 7+ seconds. But I don't have much clue about how solvers work, so wanted to double check

Thanks again!
Vu

[tkralphs]

The performance of master should be better overall than that of 2.10.3, but on any one instance, anything can happen. I think the instance you're referring to is a pure LP and as far as I know, the version of Clp (the underlying LP solver) used by 2.10.3 and the version used by master are not very different (if at all). There is probably more of an emphasis in tuning to focus on instances that are very difficult (taking minutes or hours) and not worry as much about instances that take seconds. At times, there may be some modifications to the solver that are an improvement overall, but that lead to regressions for easier instances.

[LeeU1911]

Thanks for the additional info Ted. Really appreciate it!

Best, Vu