Set the option `combined = True` to default in `az.plot_forest()`

[asael697]

The az.plot_forest() function defaults the combined option to False, but these plots' major utility is to summarize the posterior and not as a diagnostic tool. Therefore the visualization seems neater by setting combined = True, or displaying different colors for every chain.

[amrutharajashekar]

Hi, i would like to work on this issue. Thanks!

[ColCarroll]

Thanks for the input (and the volunteering!)

I'd actually vote for the option to stay True because of:

• backwards compatibility (we don't have strong guarantees, but it means something)
• what diagnostic power forest plots have might come from showing one chain was more/less dispersed than another

Happy to be outvoted -- I usually reach for plot_forest when I have lots of variables and want to see them all at once, and certainly in that case I set combined=True.

@amrutha1098 -- let's wait for at least a day or two for any other comments before deciding if this is worth picking up.

[aloctavodia]

forest plot can work both as a summarizing tool and a diagnostic tool. We even offer the option of plotting ESS and R-hat, which are diagnostic tools, and are False by default. Making combined = True increases the consistency of forestplot as summarizing tool by default and optionally a diagnostic tool.