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 |
| .hdr | Solution header file, output by XPRSwritesol (WRITESOL). | ASCII |
| .lp | LP format matrix file, input by XPRSreadprob (READPROB). | ASCII |
| .mps | MPS / XMPS format matrix file, input by XPRSreadprob (READPROB). | ASCII |
| .prt | Fixed format solution file, output by XPRSwriteprtsol (WRITEPRTSOL). | 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 |
| .json | Remote Solving Configuration file | JSON |
In the following sections we describe the formats for a number of these.
Note that CSV stands for comma-separated-values text file format.
File Compression
Many Optimizer commands support reading and writing compressed files. Support for Gzip compression is built in, so commands like the following will work as expected:
readprob problem.mat.gz writeprob problem.gz
The Optimizer can also support additional compression formats, as long as the necessary command-line tools are available in the PATH environment variable. The following table shows the supported compression formats along with the required tools:
| Extension | Required Tool |
|---|---|
| gz | Built-in support |
| zip | zip / unzip |
| tar, tgz | tar |
| bz2, bzip2 | bzip2 |
| 7z | 7z / 7za / 7zr |
| xz | xz |
| lz4 | lz4 |
| Z | compress / decompress |
In addition, the 7z tool can be used to read and write most of the formats listed above.
NB: compression using external tools is not supported in cloud environments due to security restrictions.
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