The copy-scale axis's PC-prior density

The proper density tulpa uses for the copy scale's continuum: an exponential, the penalized-complexity prior for a scale parameter with its base model at zero (Simpson et al. 2017). The rate is set by putting 5% of the prior mass above upper, so a caller that reads this off a fit's own declared grid gets the exact rate the outer integration used – rather than restating a PC-prior rate that could silently drift from it.

Usage

tulpa_hyper_copy_slab_density(upper)

Arguments

upper

The largest declared node of the copy-scale axis.

Value

A function log p(x) = log(lambda) - lambda * x, or NULL if upper is not a finite positive number.

See also

tulpa_hyper_check_copy_slab(), tulpa_joint_axis_specs_from_grid()

Examples

lp <- tulpa_hyper_copy_slab_density(upper = 2)
lp(c(0.1, 1, 2))