v.2.18.1 (24 December 2018)

Bugfix release - fixes major bug in threading where certain thread count and
job size combinations could result in incorrect output. See
https://discourse.mc-stan.org/t/bug-in-map-rect-with-threading-in-stan-2-18-0/7056
for more details.

Bug Fixes

• Fix threading batch size bug (stan-dev/math#1075)