Creating a Problem File
For manually tuning a problem, we recommend using the Optimizer console. It is flexible and it is simple to experiment with control settings here and observe the results through the output log.
Before you start experimenting with your problem, you need to save it in a file format that the Xpress Optimizer console can read. We recommend using the MPS file format since it preserves the ordering of constraints and variables. It is an unfortunate yet known fact that simply reordering constraints and variables in a mixed integer problem can lead to different solution paths and, thereby, vastly different solve times.
To truly reproduce a solve exactly from within your Mosel model or your application in the console, you can use the saved state file format, which is a binary file format. It is possible to ask the Xpress Optimizer to save its internal state to a file, from which the Optimizer console can later restore the state. This saved state file is not humanly readable and is tied to the specific platform and release version of Xpress that it was created with. Note that this saved state file also includes any changes you have made to the default control parameter settings.
How to create an MPS file depends on the type of interface you use for accessing the Xpress Optimizer:
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