documents/libman/eplex.tex

5 % License Version 1.1 (the "License"); you may not use this file except
150 if the state has been setup. If it has not, the constraint
179 Variables. If X is not yet a problem variable, it is turned into one
220     Note also that the external solver does not do any bound propagation
221     and will thus not change the bounds on its own. The default bounds for
233 	It does not impose the integer type on Vars. However, when a
247 do not place any restrictions on the variables for other eplex instances or
253 variables specified are problem variables, and does not actually place any
279     unbounded (Cost is not bounded by the constraints), then the predicate
317 my_instance}, then the {\tt eplex_instance/1} declaration is not
362   eplex_solve/1} binds the objective value, but does not bind the problem
429 In the example, only X is returned as an integer, as Y was not explicitly
442 In this case, the instance name should {\em not} be used to module-qualify
466 The external solver does not always return the optimal objective
468 the solver returns an optimal solution, it may actually not be the exact
481 is not appropriate anymore. With eplex instances, we can call {\tt
514 solution is optimal. Note also that Cost is not automatically
515 made a problem variable, and thus may not have bounds associated
516 with in. In order for the bounds information not to be lost, some bounds
542 {\tt solution(no)} indicates that we are not interested in solution values.
547 some infeasibilities that for instance could not be detected by a
616 achieved by backtracking. We do not allow the user to explicitly remove
619 For the same reason, we do not allow the objective function to be
640 with the eplex instance, and any outstanding constraints not yet collected
645 {\tt eplex_cleanup/0} will not restore the solver state, and any attempt to
646 reuse the solver state will not be possible (the execution will abort with
706 associated with that instance. If the eplex instance is {\it not\/} to be
709 without the overhead of an eplex instance. The solver state will not
716 if any {\tt TriggerModes} is specified. Otherwise, the solver is not
733 that is not taken into account by the solver by default.
773 Handle. The variables should not contain variables which are already
780 solver state represented by Handle. Failure occurs if Var is not a problem
861 that have not yet been added to the problem. When these variables are
868 non-monotonically}, and can only be used on problems that are not
869 represented by an eplex instance, and was not setup as a demon solver
905 outstanding constraints not yet collected by the solver is not removed.
939 the problem being solved, because they do not help to constrain the
946 \item they are {\it not\/} removed on backtracking. Once
956 constraints, cutpool constraints are not necessarily added to the
971 If the external solver does not produce a solution, then:
989 can be made inactive, in which case they are not considered for adding to
990 the problem matrix at all (and are not checked for violations). This is
992 constraints would not be violated by the solution, they can be made
1000 variables that may not exist after backtracking. Variables can be added to
1031 non-logical, i.e. it is not undone on backtracking.
1036 inactive because they seem to slow the solver down but do not produce
1041 As cutpool constraints are not added directly to the problem matrix, this
1053 (e.g. {\tt num_rows}) also do not include the cutpool constraints.
1058 the actual problem solved by the external solver because not all active
1098 state did not have the constraint, then it can become inconsistent with
1099 that of {\eclipse} if the equality constraint is not sent. Therefore, only
1105 condition is not tested for, because there is no longer a valid solution
1139 In many external solvers, infinities or very large numbers are not handled
1150 problem is not passed to the external solver).
1153 In addition, {\eclipse} supports numeric types that are not generally
1211 behaviour globally, it is not recommended.
1301 it is {\bf not} sufficient that you have a valid license and solver
1363  of problems with a quadratic objective is not supported for all solvers.
1372 of magnitude) between different solvers. This does not necessarily indicate
1392 API does not provide access to the root node of the MIP solve.
1402 directly access the solvers' own API to provide some functionality not
1409 Features {\bf not} supported by OSI:
1416 especially when the MIP search was not complete, such as
1448 currently CLP does not check this, and the result of trying to solve a
1449 problem with a quadratic objective not in positive semi-definite form
1460 the constraints, if those constraints are only needed by eplex and not at
1466 (SOS) are not supported. Time-outs are not supported.
1468 Another restriction is due to SYMPHONY, which does not allow the objective
1470 objective changing probes are not supported.
1477 XPRESS does not maintain an optimisation direction with the problem;
1512 solver does not have global parameters, this gets the global default value,
1517 by Handle. If the external solver does not have problem specific
1527 If the external solver does not have global parameters, this will set the