The source files in this directory create cplex, a variant of CPLEX that works with AMPL's solve command. You need to obtain libcplex.a (or libcplex.lib) and cplex.h from IBM/ILOG; see http://www.ilog.com . File makefile.u is a generic Unix makefile with comments about changes necessary for some systems. The recommended procedure is to cp makefile.u makefile and then edit makefile if necessary -- see the comments in makefile.u. The "configurehere" script automates this for some common systems. When dealing with several kinds of systems on a cross-mounted file system, you may invoke ./configure to arrange for system-specific compilations in system-specific directories, named sys.`uname -m`.`uname -s` unless otherwise specifed in $OBJDIR. (See the comments in the configure and configurehere files.) File makefile.vc is a corresponding makefile for use with Microsoft's Visual C++, e.g., via the invocation "nmake -f makefile.vc". The recommended procedure is to "copy makefile.vc makefile", edit the resulting makefile to adjust paths in it (see the comments), and then invoke "nmake". File makefile.mingw is a combination of makefile.u and makefile.vc for use with gcc in the MSys/MinGW environment: see http://www.mingw.org. README.cplex and the makefiles call the resulting solver "cplex", in accordance with examples in the AMPL book. Unrestricted versions 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 README.cplex summarizes the use of solver "cplex". File ampl110.pdf is courtesy of ILOG/CPLEX. It is a PDF file for the booklet "ILOG AMPL CPLEX System Version 11.0 User's Guide" that ILOG provides to its customers. (Though not as nicely formatted, the plain text file README.cplex is more complete in some respects.) File cplex.c is for versions 7.0, 7.1, 8.x, 9.x, 10.x, 11.x and 12.x; version.c is now folded into cplex.c. Files cplex66.c and version66.c are for version 6.6.* of CPLEX and (under compilation with -DNO_CPLEX66) for version 6.5.*. Files cplex60.c and version60.c are for version 5.0 and 6.0 of CPLEX. Files cplex4.c and version4.c are for CPLEX 4.0.