OpenSolver for Excel
The Open Source Optimization Solver for Excel
We welcome your comments on OpenSolver.
I have stumbled upon a strange behavior with a non-linear model (the Excel file had been already setup by someone else). The COIN-OR CBC didn’t complain that the problem was non-linear and found a solution, clearly sub-optimal.
The objective function is a sum of product of continuous and binary variables. Is it possible that OpenSolver has been tricked by a particular setup?
We do only quick checks for non-linearity; these checks can miss cases like yours. The user has to ensure the model is linear. Cheers, Andrew
Any thoughts when OpenSover will be comparable with MAC OSX Mojave?
I am using “Microsoft Excel for Office 365 MSO (16.0.11727.20222) 32 bit”. I downloaded “OpenSolver2.9.0_Linearwin.zip” and extracted the files to a directory. I doubled clicked on “OpenSolver.xlam” and Excel opened, but no OpenSolver commands appeared under the ‘Data” tab of the toolbar. Using “file/options/add-ins” there was no indication that OpenSolver had actually loaded.
Any assistance will be greatly appreciated!
Okay, I solved this using the instructions here:
Specifically: “Some Excel add-ins are located on your computer and can be installed or activated by clicking Browse (in the Add-Ins dialog box) to locate the add-in, and then clicking OK.”
Pleased that it worked ok. Thanks for the useful install link. Andrew
hello i want to deactivate the opensolver msg box when the solution is not optimal.
I sincerely appreciate your generosity in making this program freely available. I wanted to alert you to a bug involving named ranges. I added an OpenSolver worksheet to a financial spreadsheet that tracks my stocks and assets and has a few dozen named ranges. When OpenSolver runs, it replaces a lot of named ranges in pre-existing formulas (not OpenSolver related) in the workbook with OpenSolver-related named ranges. Perhaps if I protected those pre-existing formulas this wouldn’t happen.
Cool project. I’m using it with an Excel model written in VBA which runs much slower in Excel 2016. This lets me use the NOMAD non-linear solver with the faster Excel 2007 VBA.
Andrew may you please create a solver plugin for onlyoffice?
How does OpenSolver evaluate derivatives for non-linear problems? Does it use finite-differencing or algorithmic differentiation, like, e.g., CasADi does?
If we parse the formulae then they are differentiated by the solver, eg by using chain rule I think. The Nomad solver does not use derivatives; it uses a grid style search. Andrew
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