Clp

The COIN-OR LP code (CLP) is designed to be a high-quality simplex code provided under the terms of the Common Public License. CLP, written in C++, includes primal and dual simplex solvers as well as a barrier method for solving LPs. It is primarily intended to be used as a callable library, however, a rudimentary stand-alone executable is used to run jobs on the NEOS Server. Problems can be submitted to Clp on the NEOS server in MPS format.

The code is written primarily by John J. Forrest, now retired from IBM Research. The project is currently managed by John Forrest, Julian Hall, and the rest of the Clp team.

For information on Clp and the COIN-OR initiative, please visit the Clp COIN-OR website.

Using the NEOS Server for Clp/MPS

The user must submit a model in MPS format to solve a linear programming problem. The MPS file may be submitted in gzipped or zipped format, and NEOS will automatically uncompress it. A user also may upload a parameter file that includes Clp commands to customize the optimizer's behavior. The available commands are included below. If there is a parameter file, it must include an appropriate solve command, e.g., dualS or primalS. To print the solution values, include the line solution - after the dualS or primalS line in the parameter file.

  Double parameters:
    dualB(ound)  dualT(olerance)  preT(olerance) primalT(olerance)
    primalW(eight)  sec(onds) zeroT(olerance)
  Int parameters:
    idiot(Crash)  log(Level)  maxF(actor)  maxIt(erations)  output(Format)
    randomS(eed) sprint(Crash)
  Keyword parameters:
    allC(ommands)  chol(esky)  crash  cross(over)  direction  error(sAllowed)  fact(orization)
    keepN(ames)  mess(ages)  perturb(ation)  presolve   printi(ngOptions) scal(ing) timeM(ode)
  Actions or string parameters:
    allS(lack)  barr(ier)  basisI(n)  basisO(ut)  directory dualS(implex)  either(Simplex)
    end  exit  export gsolu(tion)  help  import  max(imize)  min(imize) para(metrics)
    primalS(implex) printM(ask)
    quit  restoreS(olution) saveS(olution)  solu(tion) solv(e) stat(istics) stop

For more help, see the Clp User Guide.