GraphPad Curve Fitting Guide

How to add your user-defined equations to the list of built-in equations

How to add your user-defined equations to the list of built-in equations

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How to add your user-defined equations to the list of built-in equations

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Prism makes it easy to add your own equations, and these will appear in the "User defined equations" group of equations. But if you want to share a set of user-defined equations with others in your lab, you can create a new group of equations that will appear underneath the ones we provide.

How to create new Equation files:

1.Start a new Prism project. Go to preferences, file and printer tab, and make sure that you are saving in .pzf format and that the "Save compact" option is not checked.

2.For each equation, either fit a data set with nonlinear regression or simulate a theoretical curve (plot a function). Reorder the results pages to the order you want the equations displayed in the equation list.

3.If a user picks your equation and clicks 'Details' they will see a small preview of the graph that is linked to the equation. Make sure this graph is easy to comprehend at small sizes.

4.When entering each equation, also consider entering a description and tip. The tip appears on the Fit tab of nonlinear regression. The description appears on the Details page.

5.When saving your equation, use a name something like this: "[Smith Lab] Flow cytometry equations", so it is very clear to anyone using Prism that these equations did not come from GraphPad (we won't be able to answer questions about them).

6.Note that each file you create will become a "folder" of equations in Prism. You'll want each file, therefore, to include a set of related equations.

How to make those equations appear with the list of built-in equations:

Windows: Move (or save) the files to the Equations folder within the Prism program folder.

Mac: Find the Prism.app file. Right (or control) click and choose Show Package Contents. You'll see the "folders" within the package. Drill down to Contents: SharedSupport:Equations. Move your equation files there. Note that by changing the prism.app file (bundle) you have changed its digital signatures. So you'll need to configure Gatekeeper to let Prism run anyway.

Both platforms:  Please do not delete any equation files that came with Prism. They are "built in" so should always be available (to prevent confusion later).

If Prism is running, quit (exit) it, then restart it. You'll now see your list of equations in the Fit tab of nonlinear regression.

Editing those equations is a bit tricky. Quit Prism, and move the file out of the Equations folder. Now restart Prism, open the file and edit it. When done, save your changes and quit Prism. Finally, move the file back to the Equations folder, and restart Prism.

Don't worry about .pze files

For every "built-in" equation file, Prism creates a .pze file. These files contain, essentially, compiled equations and so let Prism load the equations more quickly. With Windows, you'll find these deep in the Application Data folder. With Mac, they are deep in the Application Support folder and also in the Cache folder in the Equations folder in the Prism bundle.

You don't need to manage these files, and shouldn't try to. Prism will automatically create and update the needed file when necessary.