Model with no free parameters for comparison

Hi, I’m trying to compare several nested models, and one of them is just a “uniform” baseline model without any parameters. To run pm.compare I need a trace for each model, but it doesn’t look possible to “sample” and get a trace for a model with no parameters - I get ValueError: The model does not contain any free variables. Any suggestions how to do this?

Maybe you can just put a uniform RV in the model that does not connect to anything?

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Indeed, adding a variable which doesn’t affect the model at all helps - it samples, gets a trace, and pm.compare gives reasonable reesults.

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