I am comparing the posterior predictions for a simple non-linear regression problem $k= \exp(a+b/T) $, between stan and rstanarm/glm.
The prediction with rstanarm/glm is surprisingly noisy in lower part of the control variable range (see image below).
This looks like a numerical problem, but I do not know how to investigate…
Red dots are the calibration data; orange bars depict prediction 95% CI by combination of variances from the posterior.
The source code:
testArrhenius.R (2.5 KB)
Operating System: debian 9.3
Interface Version: 2.17.2