When you type the write command in the Interactive Optimizer, ILOG CPLEX displays a menu of options and prompts you for a file format, like this:

File Type Options: bas INSERT format basis file bin Binary solution file dpe Binary format for dual-perturbed problem dua MPS format of explicit dual of problem emb MPS format of (embedded) network iis Irreducibly inconsistent set (LP format) lp LP format problem file min DIMACS min-cost network-flow format of (embedded) network mps MPS format problem file mst MIP start file net CPLEX network format of (embedded) network ord Integer priority order file ppe Binary format for primal-perturbed problem pre Binary format for presolved problem qp Quadratic coefficient matrix file rew MPS format problem with generic names sav Binary matrix and basis file sos Special ordered sets file tre Branch-and-bound treesave file txt Text solution file vec Vector solution format file File type:

• The BAS format is used for storing basis information and is described in Writing Basis Files on page 50. See also Reading Basis Files on page 53.
• The BIN and TXT options create solution files. The BIN option writes a binary format solution file, while the TXT option writes an ASCII text file.
• The DPE and PPE options are used for saving perturbed problems (in SAV format).
• DUA writes out the dual formulation of a problem (in MPS format).
• EMB writes a file for an embedded network (in MPS format).
• The IIS format is used for infeasibility diagnostics.
• The LP format was discussed in Using the LP Format on page 35Writing LP Files on page 49 and Reading LP Files on page 51.
• The MIN format was developed by DIMACS to represent minimum-cost network flow problems.
• The MPS format is described in Reading MPS Files on page 52.
• The MST format allows an integer feasible solution to be saved.
• NET writes a file for an embedded network (in ILOG CPLEX format).
• The ORD format allows an integer priority order file to be written.
• PRE writes out a presolved version of the problem in SAV format.
• The QP format specifies the quadratic coefficient matrix elements.
• The REW option creates an MPS format problem file with generic names.
• The SAV format is a special binary format which facilitates very fast problem reading and writing. Because SAV format is binary (rather than ASCII text), it is not possible for you to view and edit SAV files using standard editors.
• The SOS format specifies the special ordered sets of a model.
• The TRE format saves the branch-and-bound tree for restart purposes.
• The VEC format saves the solution to a pure barrier solution, as a restart to a later crossover step.

  All these file formats are described in more detail in the ILOG CPLEX Reference Manual.