A factor of 40 speed improvement . . . that’s not something that happens the other day!

Charles Margossian and Ben Bales helped out with the Stan model for coronavirus from Riou et al. Riou reports:

You guys are amazing. We implemented your tricks and it reduced computation time from 3.5 days to … 2 hours (40 times less). This is way beyond what I expected, thank you so much!