|
Cases exist where GAMS distributes more than one version of the third party solvers. This occurs for several reasons.
| • | Alternative solver versions may be available that exploit specialized computer hardware capability. For example, there are parallel processor versions of CPLEX and XA. |
| • | Alternative solver versions may be available that incorporate enhanced capabilities, but also involve a higher licensing fee. For example, one may license CPLEX solely for simplex based linear program solutions or gain access to expanded capability versions which contains an interior point algorithm and solve mixed integer programming models. |
| • | Alternative solver versions may be available that are capable of solving different problem classes. For example, there are versions of PATH for solving mixed complementarity programs. But there are also versions that are applicable to nonlinear programming models. Similarly, there are versions of OSL specialized for stochastic programming model extensions. |
| • | Alternative software versions may be available if there are either beta test versions being distributed or experience has shown there are cases where older versions perform better in some cases. |
In the face of all of these possible alternative versions a consistent naming convention has been adopted for a few of the solvers. The following rules apply:
| • | The base name of the solver does not change (e.g. CPLEX, OSL, CONOPT, ...) and refers to the current production version. |
| • | Past and beta versions have names derived from the base name generally with a number appended or letters. |
| • | If you select the base name of a solver you will get the most recent production version of the solver. |
For example, in the release current in March 2002 the system contains CONOPT versions CONOPT1 (past), CONOPT2 (production), and CONOPT3 (future). When a solver with the base name CONOPT is identified then GAMS uses the current production version or CONOPT2.
|