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IBM LP Solutions

The LP Solutions product consists of three fully stand-alone application programs, OSLSSLV, OSLBSLV, and OSLNSLV. These programs make use of modules from the optimization library to solve linear programming problems. OSLSSLV uses the simplex method, and OSLBSLV uses an interior point method, to solve generic LP problems. OSLNSLV solves pure network programming problems using a variant of the simplex method that has been specialized for use on such problems. Because this variant takes advantage of the simple structure of the constraint matrix of pure network programming problems, and it can solve its problems up to 50 times as fast as an unspecialized simplex solver. Brief descriptions of the solver algorithms incorporated into these programs are included in the opening sections of the library User's Guide.

Each of the OSL application programs accepts many command line parameters (which may be accessed from a parameter file) to specify program options. The program options available in all the application programs include: the size of the program workspace (limited only by available memory), whether the objective is to be minimized or maximized, names of input and/or output files, and specification of new values for OSL control variables. All the settable control variables are accessible by this means. Control variables and their uses are explained in the library User's Guide.

All the application programs accept problem data (in MPS format) from stdin, and direct output to stdout. Input data may be piped in from another program, which generates the data or retrieves it from some other source, or it may be read from a file. Output may be redirected into a file in the usual way, or written directly to an output file whose name has been supplied as a program option.

OSLSSLV includes both primal and dual simplex algorithms, and OSLBSLV includes both primal and primal-dual barrier algorithms. The user may specify which algorithm is to be used, or leave the choice to the program itself. At the user's direction OSLBSLV, will switch over to the simplex method: after a specified number of iterations, if numerical difficulties are encountered, or on successful completion, to obtain a basic feasible solution. Both OSLSSLV and OSLBSLV provide access to the library modules that "scale" and "presolve" LP problems. OSLSSLV also provides access to the module that analyzes infeasible problems.

For further information about the IBM LP Solutions product, click on User Guide, to view the document, or on Download to obtain a trial copy of the programs and a sample MPS data set.

If you would like to have softcopy of the html user guide on your PC, click here to download the zipped postscript HTML (74 KB)

If you prefer to handle hardcopy of documentation click here to download either a postscript (271KB) or zipped postscript (88 KB) version of the documentation.
 
  Notes:  
  1. Viewing these postcript files is problematical. An inability to view them satisfactorily does not necessarily mean that they will not print correctly.
  2. There are no hypertext links in the postcript files, and so the cross references are undetectable.

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