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?