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Release Notes

Major releases contain substantial changes to the GAMS system. The License Check date is set to the release date of the major release.

Minor releases are mainly issued to provide bug fixes, performance improvements, and maintenance releases of solver libraries. Additionally, they can provide a few new features that do not change existing behavior. The License Check Date remains the same as for the prior major release. This means that any license file that worked with the prior major release will also work with this minor release.

Maintenance releases do not provide any new features. They are issued to provide bug fixes, performance improvements, and maintenance releases of solver libraries. The License Check Date remains the same as for the prior major release. This means that any license file that worked with the prior major release will also work with this maintenance release.

GAMS Distribution 23.3

Distribution History

23.3.3 (Maintenance release) December 17, 2009
23.3.2 (Maintenance release) November 18, 2009
23.3.1 (Major release) November 01, 2009

GAMS Maintenance Release 23.3.3 - December 17, 2009

  • MOSEK 6 rev 55 library with bug fixes
  • 32bit HAR utilities available in 64bit Windows System
  • Slow solution reporting in GAMS/Gurobi and other solvers fixed

GAMS Maintenance Release 23.3.2 - November 18, 2009

  • Gurobi 2.0.1 library with bug fixes
  • MOSEK 6 rev 53 library with bug fixes
  • Updated CoinOS library with bug fixes
  • Solver optfile bug fix in GAMSCHK
  • Synchronized tolproj (1e-8) option for solvelink=3

GAMS Major Release 23.3.1 - November 01, 2009

Acknowledgments

We would like to thank all of our users who have reported problems and made suggestions for improving this release. In particular, we thank Wolfgang Britz, Wietse Dol, Daniel T. Fokum, Nuri Gokhan, Iiro Harjunkoski, Josef Kallrath, Lloyd R. Kelly, Kristina Konold, and Uwe Schneider.

GAMS System

GAMS

  • Assigning members to a set using the asterisk is now possible in decreasing order as well. For example, the following are valid set statements in GAMS.
Set years /bc2000*bc1,0*2009/;
Set years /"-20"*"-1"/;

  • The GAMS parameters ProcDir and MaxProcDir can be used to control the generation of process directories. ProcDir=abc will use abc instead of the 225. The user is responsible to create and remove the directories. %gams.procdir% will now be defined and give you the actual process directory in use. MaxProcDir=100 will extend the usual 225a to 225z, 225aa, 225ab, etc. The defaults will be 26 for MaxProcDir and 225? for ProcDir to make everything work as before.
  • The GAMS parameter RunDir was removed.
  • The Dollar Control Options $hiddencall does the same as $call but makes sure that the statement is neither shown on the log nor the listing file. This is also true in case $ondollar or dp=2 is used. $hiddencall is especially useful in case of an encrypted model that e.g. reads/writes from an password-protected Excel file using gdxxrw password option.

GDXXRW

  • Support of the Excel 2007 file extension xlsm
  • The option password allows to pass down a password to a protect Excel file

Solvers

Baron

  • New libraries: version 9.0
  • Conopt can be used to solve nonlinear subproblems, but on 32bit platforms only (NLPSol=6)
  • More control over common linear subexpressions

Coin-OR

  • CoinScip version 1.2
    • The multi-commodity-flow network cut separator is now used by default
    • Improvements in heuristics, presolving, and branching
  • CoinGlpk version 4.39
  • CoinCouenne version 0.2
    • A separator for disjunctive cuts has been added
  • CoinCplex, CoinGurobi, CoinMosek, CoinXpress
    • These new bare bone solver links come free of charge with the GAMS Base system. General GAMS options (reslim, optcr, nodlim, iterlim) are supported. In addition an option file in the format required by the solver can be provided.
  • CoinOS 2.0
    • The new experimental link to the Optimization Services project allows you to convert instances of GAMS models into the OS instance language (OSiL) format and to let an Optimization Services Server solve your instances remotely.

GUROBI

  • New libraries: version 2.0
  • Simplex performance: The simplex optimizers are much faster in the release. The improvements are most pronounced in the dual simplex method.
  • MIP performance: The MIP solver is significantly faster as well. Part of this is a consequence of the increased speed of the dual simplex optimizer, and part is due to algorithmic improvements in the MIP itself.
  • MIP IIS: You can now compute an Irreducible Inconsistent Subsystem (IIS) for an infeasible MIP model. The previous release could only compute IISs for continuous models.
  • MIP node files: You can now store search tree nodes on disk. This allows you to solve much larger and more difficult MIP models. Use the new NodefileStart parameter to indicate how much memory you would like to devote to nodes before they are written to disk. The performance impact of putting nodes out to disk is typically quite small.

MINOS

MINOS5 (old version of MINOS) was dropped. MINOS5 now is an alias to MINOS (Version 5.51) in order to protect users that hard-coded the use of MINOS5.

MOSEK

  • New libraries: version 6.0
  • Improvement of speed and stability of the interior-point optimizer for linear and conic problems
  • More effective presolve for simplex optimizer with hot starts

XPRESS

  • New libraries: version 20.00
  • Updated licensing: multi-threaded runs and 64-bit versions now included in base license
  • Updated threads option allows specification of cores left free for non-XPRESS work.

In-core communication solver links

  • Lindoglobal supports in-core communication

Model Libraries

GAMS Data Library

  • transxls (74): Solve classical transportation problem in Excel, using vba API (gamsx, opt and gdx)

GAMS EMP Library

  • negishi (21): Pure exchange model solved with EMP, SJM, and CGE

GAMS Model Library

GAMS Test Library

Solver/Platform Availability Matrix

Solver/Platform availability - 23.3    November 1, 2009
  x86
MS Windows
x86_64
MS Windows
x86
Linux
x86_64
Linux
Sun Sparc
SOLARIS
Sun Sparc64
SOLARIS
Sun Intel
SOLARIS
IBM RS-6000
AIX 4.34
Mac PowerPC
Darwin
Mac Intel32
Darwin
Mac x86_64
Darwin
HP 9000
HP-UX 111
SGI
IRIX2
DEC Alpha
Digital Unix 4.03
ALPHAECP X X X X X X X X X X X     X
BARON 9.0 X 32bit X 32bit       8.1            
BDMLP X X X X X X X X X X X X X X
COIN X X X X     X   X X X      
CONOPT 3 X X X X X X X X X X X X X X
CPLEX 12.1 X X X X X X X 11.2   X X 10.0 9.1 8.1
DECIS X X X X X 32bit   X       X X X
DICOPT X X X X X X X X X X X X X X
GUROBI 2.0 X X X X                    
KNITRO 6.0 X X X X 5.2 32bit     5.1 X        
LINDOGLOBAL 6.0 X X X X X X     X X        
LGO X X X X X X X   X X X X X X
MILES X X X X X X X X X X X X X X
MINOS X X X X X X X X X X X X X X
MOSEK 6 X X X X 5.0 5.0 X   5.0 X X 3.2    
MPSGE X X X X X X X X X X X X X X
MSNLP X X X X X 32bit     X X X X    
NLPEC X X X X X X X X X X X X X X
OQNLP X 32bit X 32bit                    
OSL V3 X 32bit X 32bit X 32bit   X       V2 V2  
OSLSE X 32bit X 32bit X 32bit   X            
PATH X X X X X X X X X X X X X X
SBB X X X X X X X X X X X X X X
SNOPT X X X X X X X X X X X X X X
XA X 32bit X X X 32bit   X       X   X
XPRESS 20.00 X X X X X X X 18.00       16.10    
1)GAMS distribution for HP 9000/HP-UX is 22.1.
2)GAMS distribution for SGI IRIX is 22.3.
3)GAMS distribution for DEC Alpha is 22.7.
4)GAMS distribution for IBM RS-6000 AIX 4.3 is 23.1.