And thank you for your reply.
The way I imagine any Python session should save things, if it should, is to the folder from which the current Python script/Jupyter notebook is operating out of. This makes the most sense, as files and folders should be organized hierarchically on everybody’s computers, and programmers do this automatically most of the time, such as in creating a Linear Regression folder, within the PyMC3 Projects folder.
How could anyone complain if PyMC3 created either a file or folder in such a location? If this default action were not preferred by some, locating the files that have already been created would at least be easy.
As for overwriting, I believe the sound of it is counter-intuitive, as having to set (as in my case)
overwrite=True just to be able to save traces in their own visible folders, is not overwriting anything. To minimize the chances of overwriting anything, the default name for a saved object should be highly specific to PyMC3, like trace_nuts_4chains_041519.
The simplest error message I believe would be a “Save directory not specified”, and leave it at that. If something is saved, it saved there.
I hope I don’t come off as pedantic