Feedback

We welcome your comments on OpenSolver.

592 thoughts on “Feedback”

  1. Dear OpenSolver developers:

    I am a huge fan of using Excel when modelling Process Engineering simulations.

    I have been using circular references, scaling and GRG, and find it quite powerful.

    However, I sometimes miss a more powerful non linear solver, such as the ones you have implemented.

    I have been trying to use OpenSolver, but seems to get into trouble when dealing with circular references.

    May I ask you to state if this is the case? If so, are you planning on embedding OpenSolver with native circular references?

    Thank you in advance.

    1. You should add circular references as constraints. I have not tried this, but it should work. You then need to manually break the cycle yourself; the OpenSolver constraint ‘completes’ the cycle. Let us know if it works, Andrew

  2. Error in loading DLL (Error 48),Automation error (Error 440)

    Excel will report errors when running on the computer. No loss is found in the reference, but it works normally on another computer

  3. I am just thinking about using OpenSolver, and I would like to know if it is possible to define the problem in Excel and then save it as mps or gurobi file or in another syntax. Thank you.
    Milan

    1. Yes; if you open the working files directory (using the OpenSolver menu), then you can see the .lp file. But, don’t forget that OpenSolver can run Gurobi directly for you. Cheers, Andrew

    1. OpenSolver for Google Sheets is currently unavailable because of issues with changes made by Google that we are working through. Sorry about this, Andrew

  4. I tried every free solver and minimizer available free of cost.

    This is by far my favorite because it’s simple. Personally prefer this over SolverStudio because it can do what I want with minimum programming work on my side.

    My problem.
    -nonlinear
    -set constraints
    -minimizing one cell calculated in a spreadsheet
    -larger than 200 variables. (So standard solver couldn’t handle it.)

    This works. My suggestions follow
    -Nomad solver
    -On installation, it seems to work better with OpenSolver extracted into the MS Excel Addin’s folder. Specifically, if one clicks: file->options(at the bottom left)->Add-Ins-> Go (after manage in the middle with excel add-ins selected)-> browse (on analysis toolpak) -> it will take you to the addins folder. Copy OpenSolver to there.
    -when selecting constraints and variables sometimes it seems to mess up and write the same cells multiple times. Sheet1!$A$1:$C$8 is how it should look as shown in the examples. Where ‘Sheet1!” = sheet name. $A$1:$C$8 = rows and columns from A1 to C8.

    Very grateful for this OpenSolver. Well done Andrew Mason.

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