add comments

diff --git a/doc/external-libs/trilinos.html b/doc/external-libs/trilinos.html
index 84c9a3f1eac888aac2426a13c4e3ae8895cb5ed0..fdbf0cc78bfb3dc0d6eabcccd4fd12663e87e36e 100644 (file)
--- 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 d4e32482fd53dfba25cd331f2cb786c78e816598..cf8edb809826ec4f9bac835fa3f1014131f5c312 100644 (file)
--- 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.