BART: improve sampling (#5229)

* improves sampling by redrawing leafs and increasing particles

* remove linear and mix response

* update release notes

RELEASE-NOTES.md

@@ -93,9 +93,9 @@ This includes API changes we did not warn about since at least `3.11.0` (2021-01
 - `pm.DensityDist` can now accept an optional `logcdf` keyword argument to pass in a function to compute the cummulative density function of the distribution (see [5026](https://github.com/pymc-devs/pymc/pull/5026)).
 - `pm.DensityDist` can now accept an optional `get_moment` keyword argument to pass in a function to compute the moment of the distribution (see [5026](https://github.com/pymc-devs/pymc/pull/5026)).
 - New features for BART:
-  - Added linear response, increased number of trees fitted per step [5044](https://github.com/pymc-devs/pymc3/pull/5044).
   - Added partial dependence plots and individual conditional expectation plots [5091](https://github.com/pymc-devs/pymc3/pull/5091).
   - Modify how particle weights are computed. This improves accuracy of the modeled function (see [5177](https://github.com/pymc-devs/pymc3/pull/5177)).
+  - Improve sampling, increase default number of particles [5229](https://github.com/pymc-devs/pymc3/pull/5229).
 - `pm.Data` now passes additional kwargs to `aesara.shared`. [#5098](https://github.com/pymc-devs/pymc/pull/5098)
 - ...
 

pymc/bart/bart.py

@@ -67,9 +67,6 @@ class BART(NoDistribution):
     k : float
         Scale parameter for the values of the leaf nodes. Defaults to 2. Recomended to be between 1
         and 3.
-    response : str
-        How the leaf_node values are computed. Available options are ``constant`` (default),
-        ``linear`` or ``mix``.
     split_prior : array-like
         Each element of split_prior should be in the [0, 1] interval and the elements should sum to
         1. Otherwise they will be normalized.
@@ -84,7 +81,6 @@ def __new__(
         m=50,
         alpha=0.25,
         k=2,
-        response="constant",
         split_prior=None,
         **kwargs,
     ):
@@ -103,7 +99,6 @@ def __new__(
                 m=m,
                 alpha=alpha,
                 k=k,
-                response=response,
                 split_prior=split_prior,
             ),
         )()