20141124

• AMPL Solver Library version 20141121: changelog

• Add support for the objno option to gecode and jacop:

  option gecode_options 'objno=2'; # use the second objective
  

• Implement alldiff as a sub-expression in gecode, ilogcp and jacop:

  var x{1..3} integer >= 1 <= 3;
  s.t. c: if alldiff{i in 1..3} x[i] then 0 else 1;
  

  The alldiff sub-expression is transformed into a logical AND expression such as x[1] != x[2] && x[1] != x[3] && x[2] != x[3].

• Implement !alldiff in gecode, ilogcp, jacop and localsolver:

  var x{1..3} integer >= 1 <= 3;
  s.t. c: !alldiff{i in 1..3} x[i];
  

  The !alldiff expression is transformed into a logical OR expression such as x[1] == x[2] || x[1] == x[3] || x[2] == x[3].

• Distinguishes derivative evaluation errors from function evaluation errors in AMPLGSL. To avoid issues with error reporting solvers should be compiled with ASL version 20141111.

All binaries are available for download from the AMPL Open-Source Downloads page.

20141006

• Fix handling of logical constraints

All binaries are available for download from the AMPL Open-Source Downloads page.

20141002

• Cbc version 2.8.12

All binaries are available for download from the AMPL Open-Source Downloads page.

20140827

• Ipopt version 3.11.9 (changes)
• COIN-OR solvers that use Fortran (Ipopt, Bonmin and Couenne) are now linked statically with libgfortran on Linux and OS X.

All binaries are available for download from the AMPL Open-Source Downloads page.

20140630

• AMPL Solver Library version 20140617: changelog
• Gecode version 4.2.1
• JaCoP version 4.1

COIN-OR Solvers

• Bonmin version 1.7.4
• Cbc version 2.8.8
• New: Couenne (Convex Over and Under ENvelopes for Nonlinear Estimation), a COIN-OR solver for Mixed-Integer Nonlinear Programming (MINLP) problems, version 0.4.7
• Ipopt version 3.11.8

All binaries are available for download from the AMPL Open-Source Downloads page.

20140620

• AMPL Solver Library version 20140617: changelog
• Gecode version 4.2.1
• JaCoP version 4.1: announcement

COIN-OR Solvers

• New: Bonmin, an open-source solver for general mixed integer nonlinear programming (MINLP) problems, version 1.7.4
• Cbc version 2.8.8
• Ipopt version 3.11.8

All binaries are available for download from the AMPL Open-Source Downloads page.

20140508

• Include Ipopt in the distribution.

• Include gsl.ampl, the AMPL file that declares all GSL bindings and loads the amplgsl library, in the distribution. Example of use:

  include gsl.ampl;
  var x >= 1e-5;
  minimize obj: gsl_sf_gamma(x);
  

Binaries are available on the AMPL Open-Source Downloads page.

20140127

General

• Descriptions of solver options can now be written in a subset of reStructuredText which allows high-quality HTML rendering: example.
• An API for accessing the descriptions of solver options.
• Improved compatibility with older versions of Linux and Mac OS X. In particular, Linux version of amplgsl can be run on systems with glibc version 2.11.1 or later.
• Improve support of Unicode in filenames.
• Added Connecting AMPL to Oracle guide.

IBM/ILOG CP Optimizer (ilogcp)

• Merged the ilocplex driver back into ilogcp.
• Added options multiobj and objno to the ilogcp driver.

Gecode

• Updated Gecode to version 4.2.1: changelog.

CBC

• Updated CBC to version 2.8.8: changelog.

AMPLGSL

• Implemented derivatives for gsl_cdf_ugaussian_Pinv.

The downloads are available on Google Code.

20131015

Gecode

• Multiple solution support: options countsolution and solutionstub, problem suffix nsol.

• Add the suffix icl to specify integer consistency level for constraints:

  subj to c1: alldiff ({i in 1..n} q[i]) suffix icl icl_dom;
  

  The suffix and possible values for it are defined in gecode.ampl.
  Requires AMPL version 20130906 or later.

• Add support for restart search and the following options to control the search:

  • restart: restart sequence type
  • restart_base: base for geometric restart sequence
  • restart_scale: scale factor for restart sequence

• New solve results to distinguish between the cases when a solver reaches different limits:

  400     time limit
  401     node limit
  402     fail limit
  403     solution limit
  

IlogCP

• The ilogcp solver is split into two: ilogcp for the IBM ILOG CP Optimizer and ilocplex for the CPLEX Optimizer.

• Multiple solution support: options countsolution and solutionstub, problem suffix nsol.

• The element constraint. Example:

   s.t. satisfyMaxLoad{t in Trips}:
     load[t] <= element({c in TruckConfigs} MaxTruckConfigLoad[c],
                        truckConfigs[t]);
  

• The in_relation constraint. Example:

   s.t. restrictConfigOfContainer{o in Orders}:
     in_relation(configOfContainer[o],
       {c in AllowedContainerConfigs[ProductTypes[o]]} c);
  

• Multiobjective optimization.

  minimize totalCost:
     sum{t in Trips}
       (if load[t] > 0 then
         element({c in TruckConfigs} TruckCost[c],
                 truckConfigs[t])) +
     sum{t in 0..NumTrips - 2} reconfigCost[t];
  minimize tripCount: count{t in 0..NumTrips - 1} (load[t] > 0);
  

• New solve result to distinguish between the cases when a user interrupts the solution process and a solver reaches a limit:

  400     limit
  

• Add the solutionlimit option.

JaCoP

• Multiple solution support: options countsolution and solutionstub, problem suffix nsol.

• New solve result to distinguish between the cases when a user interrupts the solution process and a solver reaches a limit:

  400     limit
  

• Add the solutionlimit option.

AMPLGSL

• Update GSL to version 1.16

See also New features of the AMPL CP interfaces for the presentation of some of the new features and truckfleet.ampl for the truck fleet model used in some of the examples above.

20130830

• JaCoP
  • Report version in the solver message
  • Add the timing option that specifies whether to report setup, solution and output times
  • Fix loading jvm.dll dependencies on Windows
• IlogCP
  • Use a high-resolution steady clock for time measurement
• Gecode:
  • Add the timing option that specifies whether to report setup, solution and output times