The AMPL processors and solvers in this directory are "student" versions that restrict problem sizes (e.g., to 300 variables and 300 general constraints and objectives) and are intended for noncommercial use. For serious commercial use, you should (eventually) license commercial versions, even if your applications never exceed the limits of the student versions. See the AMPL web site http://www.ampl.com for extensive information about AMPL, including descriptions of extensions available in current versions and pointers to information about other solvers. Files with names ending in ".gz" were compressed by gzip, and files with names ending in ".tgz" are tar files compressed by gzip. In general, you need to decompress the *.gz files and make them executable. For example, you could execute gzip -dN ampl.gz cplex.tgz gjh.gz gurobi.tgz minos.gz snopt.gz tar xf cplex.tar tar xf gurobi.tar chmod +x ampl gjh minos snop rm cplex.tar gurobi.tar You may also need to move the files (using "mv" or "cp") to a directory on your search PATH. File ampl is a student version of the AMPL processor. On linear problems, it relaxes the size restriction to 500 x 500. File cplex is a student version of CPLEX 11.2.0 (for use with ampl). For pointers and more details, see files README.1st, README.cplex, and ampl110.pdf in directory /netlib/ampl/solvers/cplex. Please note that ampl110.pdf refers to "cplexamp" rather than "cplex". Unrestricted versions of cplex sold by ILOG/CPLEX are called "cplexamp" when delivered. You are free to name things as you wish (with suitable changes to "option solver" lines in AMPL scripts if necessary). One approach that avoids changes to AMPL scripts is to call the interactive CPLEX front end provided by ILOG/CPLEX "icplex" rather than "cplex", and to use "cplex" for the solver that works with AMPL. File gjh computes gradients, Jacobian matrices and Hessians of nonlinear problems and makes them available to AMPL as parameters. File gurobi.tgz contains a student version of the GUROBI solver for linear and mixed-integer problems; it limits problem sizes to 500 x 500, unless you have a GUROBI license that allows larger problem sizes -- and have set $GRB_LICENSE_FILE to the (full path) name of the GUROBI license file (which can be done within an AMPL session by an "option GRB_LICENSE_FILE ..." command). See the README.gurobi file in gurobi.tgz for installation instructions. File minos is a student version of MINOS (for use with ampl). For pointers and more details, see files README.1st and README.minos in directory /netlib/ampl/solvers/minos and see web page http://www.ampl.com/REFS/abstracts.html#ampl-minos . File snopt is a student version of SNOPT (for use with ampl). For pointers and more details, see file README in directory /netlib/ampl/solvers/snopt.