CPLEX Optimization, Inc., was founded in 1988 with the mission of providing the highest-performance optimizers for linear programming. CPLEX was the first commercial linear programming optimizer developed in the "C" programming language. The first CPLEX products were CPLEX Linear Optimizer and CPLEX Callable Library.

The name "CPLEX" comes from the combination of the letter "C" for the programming language, and the word "simplex" for the simplex method for linear programming.

Milestones
Significant milestones in the history of CPLEX include:

• October, 2007—CPLEX 11.0 is released, with breakthrough performance gains for mixed integer programming (MIP) models and enhanced parallel MIP optimization. The MIP solution pool feature and the performance tuning utility are introduced.

• January 2006—CPLEX 10.0 is released, with performance improvements in the primal simplex and barrier methods, as well as the MIP optimizer. Indicator constraints and solution polishing heuristics are introduced and improvements to infeasibility analysis are made.

• December 2003—CPLEX 9.0 is released, with performance improvements in primal and dual simplex methods and the MIP optimizer. It includes ILOG Concert Technology for .NET users and support for quadratically constrained programs.

• July 2002—CPLEX 8.0 is released, with MIP performance improvements and support for mixed integer quadratic programs.

• December 2001—CPLEX 7.5 is released, including ILOG Concert Technology for Java users.

• October 2000—CPLEX 7.0 is released, including ILOG Concert Technology for C++ users.

• March 1999—CPLEX 6.5 is released, with significant performance improvements in primal and dual simplex methods, and CPLEX Mixed Integer Optimizer.

• April 1998—CPLEX 6.0 is released, with significant performance improvements in primal and dual simplex methods, and CPLEX Barrier Optimizer.

• September 1997—CPLEX 5.0 is released, with a new memory model for easy C++ integration.

• August 1997—ILOG acquires CPLEX Optimization, Inc.

• March 1996—Parallel CPLEX Mixed Integer Solver is introduced.

• December 1995—CPLEX 4.0 is released, with a redesigned advanced programming interface (API) to allow thread-safe applications.

• March 1995—Parallel CPLEX Barrier Solver is introduced

• April 1994—CPLEX 3.0 is released, including CPLEX Barrier Solver.

• March 1993—CPLEX 2.1 is released, including CPLEX presolve algorithms.

• April 1992—CPLEX 2.0 is released.

• 1991—CPLEX 1.2 is released, with support for the dual simplex method and CPLEX Mixed Integer Optimizer.

• 1988—CPLEX 1.0 is released, with support for the primal simplex method.

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