use postprocessor value in ParsedMaterial?

[jessecarterMOOSE]

I'd like to use a postprocessor value in my ParsedMaterial. I tried to put the name in the 'args' list but that didn't work because it seems to be looking for variables. I suppose I could make an AuxVariable that holds the postprocessor value everywhere, but that seems to be a bit overkill. Is there a better way?

[dschwen]

No, there isn't a better way yet, sorry. It would not be hard to add that capability though.

[tophmatthews]

What about holding the postprocessor as a function instead of an aux? Still an extra step, but at least it's not an aux defined everywhere?

[jessecarterMOOSE]

Makes sense 👍

[dschwen]

Well, that's a possibility, but it doesn't really answer the question, because to get a Function value into a ParsedMaterial you'd have to use another step - either FunctionAux or GenericFunctionMaterial :-D (the latter would be more memory efficient)

[tophmatthews]

oh ya...what a pain...

[dschwen]

To make this a markable answer: Use a GenericFunctionMaterial to capture the PostProcessor value and add it to ParsedMaterial using the material_property_names parameter.

[tophmatthews]

Or bug @dschwen enough until he adds the capability you need :)

[jessecarterMOOSE]

I ended up using @tophmatthews 's suggestion because what I was actually, secretly doing was using the material to mark a region either 0 or 1 and then integrating that material with a postprocessor to find the area fraction of that marker, then normalize that value by another postprocessor. Dividing the area fraction postprocessor value by the other in a ParsedFunction was all that was required. Guess I should have been more clear on what I was after. Though to @dschwen 's credit, using the GenericFunctionMaterial would have worked too. Both require an extra step.

What would also be neat is a ParsedPostprocessor where I can just divide the two postprocessors directly instead of making the intermediate function. Then you might be able to get rid of Difference, LinearCombination, and Scale postprocessors, and maybe a few others.