definition variables are predictors

[brandmaier]

semtree does not detect that definition variables are part of the model and uses them as splitters.

[manuelarnold]

Is this fixed? There are no issues if the predictor argument in the semtree function is used.
If not: we could either check if the OpenMx model contains definition variables and, if so, give an error that definition variables require the use of the predictor argument or make the predictor argument mandatory in the first place. I prefer the latter option.

[brandmaier]

There is a new heuristic to extract def variables from OpenMx models: 985c95f
This needs to be integrated in semtree() and semforest() calls.