Change default acquisition function back to MES

PVRS turned out to be too explorative in high dimensions which makes it
an unsuitable choice as default acquisition function.
PVRS is still a very robust choice for 3 or less parameters.

docs/parameters.myst

@@ -142,10 +142,10 @@ fitting process:
 * - `"acq_function"`
   - `-a --acq-function TEXT`
   - The search strategy used by the tuner. The following values are possible:
-    * `"mes"`: Max-value entropy search tries to sample points which
+    * `"mes"` (default): Max-value entropy search tries to sample points which
       yield a lot of information about the value of the optimum.
       A good allrounder strategy leaning on the exploitative side.
-    * `"pvrs"` (default): Predictive variance reduction search tries to sample
+    * `"pvrs"`: Predictive variance reduction search tries to sample
       points which reduce the uncertainty of promising regions as much as
       possible. Another good allrounder strategy, which compared to `mes`
       focuses more on exploration. Is slightly more robust.

tune/cli.py

@@ -109,7 +109,7 @@ def run_server(verbose, logfile, command, experiment_file, dbconfig):
 @click.option(
     "-a",
     "--acq-function",
-    default="pvrs",
+    default="mes",
     help="Acquisition function to use for selecting points to try. "
     "Can be {mes, pvrs, ei, ts, vr}.",
     show_default=True,
@@ -236,7 +236,7 @@ def run_server(verbose, logfile, command, experiment_file, dbconfig):
 )
 def local(  # noqa: C901
     tuning_config,
-    acq_function="pvrs",
+    acq_function="mes",
     acq_function_samples=1,
     confidence=0.9,
     data_path=None,