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 22.8
|22.8.1||(Major release)||August 01, 2008|
GAMS Major Release 22.8.1 - August 01, 2008
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, Andrea Consiglio, Anton Eremeev, Mustafa Esen,Josef Kallrath, Erwin Kalvelagen, Todd Munson, Rich Roberts, and Andres Ramos.
- GAMS scratch file extension: Starting with distribution 22.9 the default file extension of intermediate files located in the 225? directories will change from
.dat. For distribution 22.8 it is still
.scr. The scratch extension now is a parameter that can be changed with the GAMS option
gams trnsport scrext=tmp. Within GAMS code you get the scratch extension using %
- Increased the maximum input line length to 40,000 characters and the maximum number of columns in a table to 10,000.
- Checking for an interrupt is now also done inside a GAMS looping constructs.
$LOADdirective can read the universe from a gdx file by specifying
- Certain gdx file read operations are now faster and use less memory.
- GAMS parameters
- Allow new gdx files to be written in an older format of the gdx file.
- Usage through an environment variables (valid for all gdx related operations):
gdxconvert = <value>and
gdxcompress = <value>or via GAMS command line parameters:
gdxconvert = <value>and
gdxcompress = <value>.
- Possible values for
0(or empty): no compression
1: compression turned on
- Possible values for
V7: version 7
V6: version 6
V5: version 5
- E. g. to get a compressed v6 gdx file enter:
gams <model_name> gdxconvert=v6 gdxcompress=1 gdx=<gdx_file>.
- With GAMS 22.8 the default format for gdx files is V7 uncompressed.
- Only V6 and V7 support compression.
- V7 formatted files were introduced with version 22.6 of GAMS; V6 formatted files were introduced with version 22.3 of GAMS. GAMS platforms that were introduced after 22.3/22.6 (e.g. Mac Intel or SunSparc64) do not support V5/V6.
- The command line options have a higher precedence as the environment variables with the same name.
gdx2xls: Converts an entire gdx data container to a Microsoft Excel spread sheet.
invert: Calculates the inverse of a matrix provided as a gdx file (for more information see gdxutils documentation).
msappavail: Checks which Microsoft Office programs are installed.
xlstalk: Allows some interaction with Excel to open/close/save Excel files.
gdxcopy: New option to replace existing gdx files.
gdxdiffNew id option to compare specified ids only.
gdxmergeNew optional output parameter to specify the name of the output file.
gdxviewer: Fixed problem with cube view.
Fixed problem when moving a column to the plane in the gdx data viewer.
New models, including tests for
- poly function
GAMS introduces the new model library 'GAMS Data Utilities' containing models that demonstrate the various utilities to interface GAMS with other applications.
The models of the forthcoming book PRACTICAL FINANCIAL OPTIMIZATION - A Library of GAMS Models by Andrea Coniglio, Soren Nielsen, and Stavros A. Zenios have been included in the GAMS distribution. It is a companion volume to the book Practical Financial Optimization by Stavros A. Zenios.
New libraries 8.1.5 for Windows, Linux, and AIX
GAMS 22.8 introduces a third experimental solver BDMLPD besides
CONOPTD and CPLEXD. They are very similar compared to their
professional brothers BDMLP, CONOPT and CPLEX. They lack some
functionality (e.g. CPLEXD does not solve QCP models) but offer in-core
communication between GAMS and the solver. No large model scratch files
need to be written to disk which can save time if you solve many models
in your GAMS program. This in-core execution is activated by setting
<modelname>.solvelink=5; before the solve statement.
- New libraries 0.99
- Support of user-defined cut generators and heuristics via BCH (Branch and Cut Heuristic)
- CoinCbc new libraries 2.1
- CoinScip supports user-defined cut generators, heuristics, and incumbent report callbacks via BCH
New option hessian to dump the Hessian matrix into a GDX file. Similar to the option jacobian.
New libraries 11.1.1
New libraries 22.214.171.1242. Sun Sparc Solaris 126.96.36.1994.
New libraries 5 Rev 90
New libraries for Windows
|Solver/Platform availability - 22.8 August 1, 2008|
Digital Unix 4.03
|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.|