Author: Andrew Mason (Team OpenSolver)

Excel updates crashing OpenSolver

1) A recent update to Excel has blocked access to the “OpenSolverNomad.dll” file that we use to execute the NOMAD solver. Symptoms of this include the “About OpenSolver” window crashing with an error. Errors also occur when trying to use the NOMAD solver. We don’t currently have work around for this. We would welcome user feedback on any settings change that lets Excel use this DLL. Please email email hidden; JavaScript is required if you have a solution that works.

2) According to StackOverflow, a recent update has also changed the default ActiveX settings in Excel to a stricter level. This disables controls from external libraries like RefEdit; we use RefEdit in our dialogs. So, in recent Excel versions, permission to use ActiveX controls must be turned on in the Excel Trust center (under File…. Options… Trust Center… Trust Center Setting). More details are in our help pages.

OpenSolver helping solve Arson Cases

Chaney Ganninger at the West Virgina University is using OpenSolver to help model accelerants used in arson cases. Amazing where optimisation ends up being helpful!

Check out Chaney’s thesis:

Refinement of a thermodynamic model to explain the weathering
patterns of ignitable liquids on household substrates at elevatedpatterns of ignitable liquids on household substrates at elevated
temperatures

at https://researchrepository.wvu.edu/cgi/viewcontent.cgi?article=13611&context=etd

500,000 downloads

Today (10 Dec 2020) was a big day for OpenSolver, as we rolled past the 500,000 downloads count. Many thanks to all our Engineering Science (University of Auckland) students who have worked on this over the last decade, with a really large thank you to Jack Dunn for his major contributions over many years (including creating the Mac version). The community feedback is also much appreciated – thanks for letting us know of issues and suggesting enhancements. Cheers, Andrew

New Support Site for CBC Solver

Most of our OpenSolver users choose the standard integer programming solver, CBC (which is the default option). COIN-OR, the non-profit who support and develop CBC, have just announced a new support forum for CBC users. (This is a beta test of the new GitHub discussion forums being developed.) This is the best place for advanced users to take technical questions, such as queries about CBC parameters (which OpenSolver supports). Andrew

OpenSolver 2.9.3 Beta Release

Hi everyone,

We have now released OpenSolver 2.9.3 for beta testing! You can download this new version of OpenSolver on https://sourceforge.net/projects/opensolver/files/. Below are the release notes that cover the changes made in this new version of OpenSolver:

v2.9.3 – 2020/03/02

  • Added support for using Gurobi 9.0
  • Added a temp fix for running consecutive operations on Excel64bit

v2.9.2 – 2019-02-04

  • Add support for NEOS CPLEX as a new solver.
  • Add import LP file feature.
  • Add Examples files and submenu.
  • Fix memory error when solving consecutive non-linear models in 64bit.

As always, we welcome any feedback! Please comment below if it works ok, or if there are any issues encountered, or if you have any questions regarding the new release. Thanks!

OpenSolver for Google Sheets currently down for new users

12 Feb 2020: It was raised to us that OpenSolver for GoogleSheets is still unaccessible to new users. We are now able to replicate this bug. From our tests, new user accounts are able to install OpenSolver for Google Sheets as an Add-on from Chrome Web Store. However, the “Sign in with Google is temporarily disabled for this app” screen will still show up when trying to open the sidebar from the ribbon. We are very sorry for the inconvenience and we have contacted Google regarding this issue. We need to wait for Google’s response on this, therefore we are unsure of when this problem will be fixed.

10 Feb 2020: This is no longer the case! OpenSolver for Google Sheets is now back online for new user installations. The “app isn’t verified” screen will no longer show up for new installations. We have also updated our privacy policy to align with Google’s requirements. For more information on the usage of Google OAuth scopes please visit our OpenSolver for Google Sheets page and our Privacy Policy page.

Original post: Changes made by Google mean that OpenSolver for Googlesheets is currently not working for new users who want to add it to their Googlesheets. (Apparently the first 100 users each month can sign in, but then further sign ins are blocked by Google.) We are working on fixing this, But we don’t know how long it will take, sorry. We suggest you use OpenSolver for Excel until we get it working properly for Googlesheets.

Sorry for the inconvenience.

Cheers,

Andrew

OpenSolver for Ecological Conservation

We justc ame across an interesting article using OpenSolver to help develop optimal policies for conservation.

https://esajournals.onlinelibrary.wiley.com/doi/full/10.1002/ecs2.2596

Commonalities in stream connectivity restoration alternatives: an attempt to simplify barrier removal optimization

Ryan A. McManamayJoshuah S. PerkinHenriette I. Jager First published: 07 February 2019 https://doi.org/10.1002/ecs2.2596

https://esajournals.onlinelibrary.wiley.com/doi/full/10.1002/ecs2.2596

Ecosphere banner


250k milestone

Today the download odometer rolled past another milestone:

Thanks to all our users and our development team (and most recently Jack Dunn) for supporting OpenSolver for the last 6 years. None of this would have been possible without the solvers from COIN-OR; thanks to John Forrest and Ted Ralphs for the many years of CBC development, without which the OpenSolver project would never have started.

Andrew