Similar things are happening in galaxy formation too; numerical models here cost tens of thousands - tens of millions of cpu hours to run, and have maybe 8-10 free parameters. We use emulators based upon a training set of maybe 100-200 real simulations to calibrate out those free parameters to scaling relations (e.g. sizes of galaxies v.s. their mass).

Odd that they did not mention these when discussing sub-grid modelling, as afaik these Astronomy simulations (along with planetary impacts) are probably some of the first to have used them…