From: Timo Heister <timo.heister@gmail.com>
Date: Mon, 3 Feb 2020 18:30:02 +0000 (-0500)
Subject: add comments
X-Git-Tag: v9.2.0-rc1~546^2~1
X-Git-Url: https://gitweb.dealii.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=f507746b24d2c6e0496a5b2fd3a1cddc36d58fd1;p=dealii.git

add comments
---

diff --git a/doc/external-libs/trilinos.html b/doc/external-libs/trilinos.html
index 84c9a3f1ea..fdbf0cc78b 100644
--- a/doc/external-libs/trilinos.html
+++ b/doc/external-libs/trilinos.html
@@ -63,7 +63,7 @@
         <li> EpetraExt (optional),
         <li> Ifpack,
         <li> ML,
-        <li> MueLu (optional),
+        <li> MueLu (optional, required for TrilinosWrappers::PreconditionAMGMueLu),
         <li> ROL (optional),
         <li> Sacado (optional),
         <li> Teuchos,
diff --git a/include/deal.II/lac/trilinos_precondition.h b/include/deal.II/lac/trilinos_precondition.h
index d4e32482fd..cf8edb8098 100644
--- a/include/deal.II/lac/trilinos_precondition.h
+++ b/include/deal.II/lac/trilinos_precondition.h
@@ -1725,6 +1725,9 @@ namespace TrilinosWrappers
    * except for the higher_order_elements parameter which does not exist in
    * PreconditionerAMGMueLu.
    *
+   * @note You need to configure Trilinos with MueLU support for this
+   * preconditioner to work.
+   *
    * @note At the moment 64bit-indices are not supported.
    *
    * @warning This interface should not be considered as stable.