Feedback

We welcome your comments on OpenSolver.

532 thoughts on “Feedback”

  1. 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.

    1. OpenSolver does not change any formulae. Perhaps Excel is changing how the formulae are being displayed? Could you email us a screenshot, and the text from About OpenSolver giving the Excel version etc, to email hidden; JavaScript is required . Thanks, Andrew

  2. 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.

  3. How does OpenSolver evaluate derivatives for non-linear problems? Does it use finite-differencing or algorithmic differentiation, like, e.g., CasADi does?

    1. 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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