message: Clarify adaptive block-Jacobi documentation
diff: @@ -268,10 +268,12 @@ protected:
  * that has to be read to apply the precondidionter.
  *
  * However, there is a trade-off in terms of longer preconditioner generation
  - * due to extra work required to compute the condition numbers.
  + * due to extra work required to compute the condition numbers. This step is
  + * necessary to preserve the regularity of the diagonal blocks.
  *
  - * @tparam ValueType highest precision of matrix elements and the precision of
  - * vectors used for the apply() method
  + * @tparam ValueType highest precision of matrix elements, the precision of
  + * vectors used for the apply() method and the precision in
  + * which all computation is performed
  * @tparam IndexType integral type used to store pointers to the start of each
  * block
  */
  @@ -502,8 +504,9 @@ protected:
  * and possibly improve the performance of preconditioner application.
  * For more details see the documentation for BlockJacobi.
  *
  - * @tparam ValueType highest precision of matrix elements and the precision of
  - * vectors used for the LinOp::apply() method
  + * @tparam ValueType highest precision of matrix elements, the precision of
  + * vectors used for the LinOp::apply() method and the
  + * precision in which all computation is performed
  * @tparam IndexType integral type used to store pointers to the start of each
  * block
  */
  