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2011-03-05 16:01:03 -0600 commented answer Sage 4.6.2: how to use CPLEX

Thanks. This made some progress. After following the instructions, I get an undefined symbol error in one of the Cbc object files (libCbcSolver.so.0) if I use solver="Coin". I don't mind that, as it's really CPLEX that concerns me. Using solver="CPLEX" works fine in a terminal; I can construct and solve a small test problem. In a notebook, though, lp = MixedIntegerLinearProgram(solver="CPLEX") fails silently -- it produces no output (in the terminal I see a license message from CPLEX), no error message, and lp is considered undefined.

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2011-03-05 15:16:45 -0600 marked best answer Sage 4.6.2: how to use CPLEX

In order to use the COIN solver within Sage you have to have the cbc pacakge installed. It can be easily installed with :

sage -i cbc

After the cbc package installed, run

sage -br

to build the new backend module for COIN. Then, you'll be able to run

lp = MixedIntegerLinearProgram(solver="Coin")

CPLEX is a little trickier, but there is documentation you can find documentation at http://www.sagemath.org/doc/thematic_tutorials/linear_programming.html#installing-cplex .

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2011-03-05 11:37:01 -0600 asked a question Sage 4.6.2: how to use CPLEX

I've just upgraded from 4.6 to 4.6.2. The COIN and CPLEX backends were included (in .../devel/sage-main/sage/numerical/backends), but I can't find a way to import them. The line

lp = MixedIntegerLinearProgram(solver="GLPK");

works, but solver="Coin" and solver="CPLEX" lead to messages that the corresponding _backend module is not found. I tried a few blind guesses to import them but had not luck. The docs seem to be a lap behind (the help for MixedIntegerLinearProgram says the CPLEX interface is not implemented yet, but that COIN's is; on the other hand, asking for help for sage.numerical.backends.xxxx_backend works for xxxx=glpk but not for xxxx=coin or cplex).

Does anybody know the correct incantation?

TIA, Paul