Fixed effect in posterior simulation vignette

[jonathonmellor]

Hi Gavin,

As always, thank you for your great work on this package.

Would it be possible to add to the posterior simulation vignette what your preferred method is for doing inference on fixed effects, in addition to the existing docs on smooth terms.

An example would be if I wanted to extract the intercept from a y ~ 1 + s(x) model - what would be the preferred way? My current thinking is via gratia::generate_draws() with some indexing of the returned value based on the order of terms, but I'm wondering if there is another way that's more gratia-y.

If I've just missed something please do let me know!

[gavinsimpson]

@jonathonmellor I'd need to have a little think about this. I suspect that I would use fitted_samples() or posterior_samples() and then use the terms argument to mgcv::predict.gam(), which those gratia functions pass along, to select only the model intercept.