Installation Notes

[ankane]

Hey @gverger, thanks for this great library! I wanted to share some notes about installation that can hopefully be incorporated into the readme.

I think this line is outdated with the release of cbc-wrapper 2.9.9.4.

The gem includes a version of the Coin-Or Cbc library. If the system on which it is installed is not Linux 64bits, it downloads the library sources and recompiles them at installation.

On Ubuntu, users need to do:

sudo apt install coinor-libcbc-dev

On Heroku, I was able to get it working with the Apt buildpack with an Aptfile of:

coinor-libcbc-dev

And setting LD_LIBRARY_PATH so it can find LAPACK and BLAS.

heroku config:set LD_LIBRARY_PATH=/app/.apt/usr/lib/x86_64-linux-gnu/lapack:/app/.apt/usr/lib/x86_64-linux-gnu/blas 

The last part is needed due to this issue, or it'll fail at runtime with liblapack.so.3: cannot open shared object file: No such file or directory - /app/vendor/bundle/ruby/2.6.0/gems/cbc-wrapper-2.9.9.4/ext/cbc-wrapper/cbc_wrapper.so.

I also tried an older cbc-wrapper on Heroku without the Apt buildpack (gem "cbc-wrapper", "2.9.9.3"), and it installs, but fails at runtime with libCgl.so.1: cannot open shared object file: No such file or directory - /app/vendor/bundle/ruby/2.6.0/gems/cbc-wrapper-2.9.9.3/ext/cbc-wrapper/cbc_wrapper.so (LoadError).

Hopefully this is helpful to other users.

[gverger]

Hello @ankane, thank you for the feedback, it seems very useful indeed :)

Do you want to open a PR with the change to the readme? I can do it myself too, no problem

[ankane]

Thanks @gverger, will defer to you to incorporate in whichever way you think is best.

[ankane]

Quick follow up: Mac users can now install CBC with brew install cbc (and the gem picks it up).

[gverger]

Thanks @ankane I've updated the readme. Your feedback was precious

[ankane]

Thanks @gverger, looks great. Love how easy the gem is to use.