Changelog and patch bump

Author: penelopeysm

HISTORY.md

@@ -1,5 +1,15 @@
 # DynamicPPL Changelog
 
+## 0.38.9
+
+Added `DynamicPPL.Experimental.FastLDF`, a version of `LogDensityFunction` that provides performance improvements on the order of 2–10× for both model evaluation as well as automatic differentiation.
+Exact speedups depend on the model size: larger models have less significant speedups because the bulk of the work is done in calls to `logpdf`.
+
+Please note that `FastLDF` is currently considered internal and its API may change without warning.
+We intend to replace `LogDensityFunction` with `FastLDF` in a release in the near future, but until then we recommend not using it.
+
+For more information about `FastLDF`, please see https://github.com/TuringLang/DynamicPPL.jl/pull/1113 as well as the `src/fasteval.jl` file, which contains extensive comments.
+
 ## 0.38.8
 
 Added a new exported struct, `DynamicPPL.ParamsWithStats`.

Project.toml

@@ -1,6 +1,6 @@
 name = "DynamicPPL"
 uuid = "366bfd00-2699-11ea-058f-f148b4cae6d8"
-version = "0.38.8"
+version = "0.38.9"
 
 [deps]
 ADTypes = "47edcb42-4c32-4615-8424-f2b9edc5f35b"