Category Archives: Releases

SolverStudio 00_05_00_00 20130228 is our latest beta release. It adds lots of new features which we would welcome feedback on. This new version has been developed by Oscar Dowson of Engineering Science (University of Auckland), who has done an amazing job getting up to speed with the code. We are also grateful to GAMS for providing the DLL’s we use to access GDX files. The changes include:
1/ Added COOPR support + examples
2/ Added SimPy support + examples
3/ Changed Gurobi support to use Gurobi’s Python environment, meaning a full Python install is not needed. Added Gurobi License Manager + examples
4/ Added GAMS on NEOS support + examples
5/ Added integrated GAMS GDX file support via C# API
6/ Changed GAMS to use GDX files
7/ Changed the GAMS data command to $GDXIN “SheetData.gdx” in models
8/ Changed the GAMS display command
9/ Changed wording of help text in the Ribbon Menu (previously said ‘Python PuLP’ regardless of language
10/ Added a Fix Minor Errors command to AMPL. This will correct choice of Solver, and missing data, solve and display commands.
11/ Added compression for large files being sent to NEOS
12/ Added menu items to select choice of solver on NEOS; this is written to the model in AMPL as an AMPL ‘option’, and stored (invisibily) with GAMS.
13/ Split examples into different workbooks
14/ Removed CPython from SolverStudio download. Now requires user to install manually if needed
15/ Added lines to data items in Highlight Data Items and Data Items Editor to show direction of tuples
16/ Added the ability to resize the Data Items Editor
17/ Added local precedence to the Data Items Editor. Creating an items with the same name as a global hides the global. Deleting the local shows the global.
18/ Added code to parse complex AMPL output; option_display_1col99999999 no longer needed
19/ Added option to choose NEOS queue (long/short).
20/ Fixed bug where sheets with single quotes ‘ in their name failed to find Data Items or solve
21/ Updated About Box
22/ Removed need to for ugly AMPL display options command
23/ The code is now signed using a Comodo certificate
24/ Registry settings now store (and remember) the model-window’s font size
25/ Added support for storing ‘settings’ such as the choice of solver in the spreadsheet along with the model
26/ Improved handling of data items to allow sets to have missing items (which are skipped) and to contain ‘uneven’ tuples (ie tuples with different lengths in the same set). Indexed sets can also contain values (but not indices) that can be uneven tuples. Any set used for indexing needs to have tuples of all the same length (being the number of rows or columns used to define the index). Indexed sets of tuples (even and uneven) can now be written to.

SolverStudio_00_04_09_26 20121015 fixes an AMPL on NEOS bug that was stopping unindexed variables being written to the sheet (thanks, Suresh, for reporting this), and addresses a long standing issue with the editor slowing down on big files. Andrew

The latest version of SolverStudio (SolverStudio_00_04_08_24, dated 2012.10.10) has now been uploaded. The big new feature of this is support for running AMPL models in the cloud using the NEOS server; simply choose “AMPL on NEOS” as your language. Everything works as it does for AMPL, including output back to the spreadsheet, and choosing the Solver using the AMPL standard command “option solver <solvername>”. You can use any solver on NEOS with AMPL support; see this list.  Thanks, NEOS and AMPL, for making this cloud service available; it is a great contribution to the OR community.

The SolverStudio_00_04_06_22 release focusses on improvements for AMPL, the main one being a menu item to display the data file in an Excel task pane. (This feature is also available for GMPL.) The displayed file is updated each time the model is run. The examples have been further improved, and should work by default using the free student version of AMPL. A print command has also been added to print models and their output.

The latest version of SolverStudio (2012.08.27) is now available for testing. This has numerous fixes and improvements, including better AMPL support, a fix for a bug that could erase your model, and speed improvements when writing data back to a sheet. The examples have been improved and extended. Thanks to my Engineering Science students for their feedback, and to Stu Mitchell for his testing with PuLP. All feedback welcome.

The latest SolverStudio release, most significantly, adds a Cancel button that appears only when solving large models. During a long run, it is now possible to minimise Excel (although you may have to Alt-Tab to bring it back as the task bar sometimes fails). Other smaller changes are included, such as making default values for indexed parameters work in CPython, adding an Uninstall button in the About box, and adding a Python example where we plot the cost as a constraint right hand side is changed. As usual, all feedback is welcome (particularly on the Cancel button). Andrew

SolverStudio version 00_04_01_14 (2011.01.16) fixes a missing DLL problem that resulted in a Python error (missing module “re”).

An issue regarding Python encodings has been reported when using CPython (termed “Python (external)” by SolverStudio); this is still being investigated, and may occur on non-English systems. Any further reports of this would be appreciated.

This version is a new upload replacing SolverStudio_00_04_01_12 20120108.zip, which was corrupted during the upload. Sorry about that. Andrew

The latest version of SolverStudio has been uploaded, and now features support for PuLP, AMPL (either a licensed version, or a student version downloaded by the user using SolverStudio), the GNU Math Programming Language GMPL (an AMPL look-alike, included with SolverStudio), GAMS (which must be installed by the user), and any Python code that works either under IronPython or the more standard Python (known as CPython), which is now included with the SolverStudio download. All feedback welcome.

Andrew

PS: Thanks for feedback from Max and Tom which has improved this version, and to Stu Mitchell for improving PuLP to work around limitations in IronPython. (This arose due to operator overloading which meant sorting doesn’t work in IronPython, but does work in standard Python.)

PPS: This download is somewhat larger as it includes a full CPython and the Gnu Linear Programming Kit (GLPK).

OpenSolver Studio has now been released as a version 0.1 beta. Please let us know how you go installing this – we’d love your feedback. Andrew