File Types
The Optimizer generates or inputs a number of files of various types as part of the solution process. By default these all take file names governed by the problem name (problem_name), but distinguished by their three letter extension. The file types associated with the Optimizer are as follows:
| Extension | Description | File Type | 
|---|---|---|
| .alt | Matrix alteration file, input by XPRSalter (ALTER). | ASCII | 
| .asc | CSV format solution file, output by XPRSwritesol (WRITESOL). | ASCII | 
| .bss | Basis file, output by XPRSwritebasis (WRITEBASIS), input by XPRSreadbasis (READBASIS). | ASCII | 
| .csv | Output file, output by XPRSiiswrite. | ASCII | 
| .dir | Directives file (MIP only), input by XPRSreaddirs (READDIRS). | ASCII | 
| .glb | Global file (MIP only), used by XPRSglobal (GLOBAL). | Binary | 
| .gol | Goal programming input file, input byXPRSgoal (GOAL). | ASCII | 
| .grp | Goal programming output file, output byXPRSgoal (GOAL). | ASCII | 
| .hdr | Solution header file, output by XPRSwritesol (WRITESOL) and XPRSwriterange (WRITERANGE). | ASCII | 
| .lp | LP format matrix file, input by XPRSreadprob (READPROB). | ASCII | 
| .mat | MPS / XMPS format matrix file, input by XPRSreadprob (READPROB). | ASCII | 
| .prt | Fixed format solution file, output by XPRSwriteprtsol (WRITEPRTSOL). | ASCII | 
| .rng | Range file, output by XPRSrange (RANGE). | Binary | 
| .rrt | Fixed format range file, output by XPRSwriteprtrange (WRITEPRTRANGE). | ASCII | 
| .rsc | CSV format range file, output by XPRSwriterange (WRITERANGE). | ASCII | 
| .sol | Solution file created by XPRSwritebinsol (WRITEBINSOL). | Binary | 
| .slx | Solution file created by XPRSwriteslxsol (WRITESLXSOL). | ASCII | 
| .xtm | Tuner method created by XPRStunerwritemethod. | ASCII | 
| .xtr | Tuner result created by XPRStune. | XML | 
In the following sections we describe the formats for a number of these.
Note that CSV stands for comma-separated-values text file format.
 
