Warn that this is not really an a posteriori error estimator

git-svn-id: https://svn.dealii.org/trunk@24061 0785d39b-7218-0410-832d-ea1e28bc413d

diff --git a/deal.II/include/deal.II/numerics/error_estimator.h b/deal.II/include/deal.II/numerics/error_estimator.h
index 82291b2efb363052d3d3d62fcaa73a32a13a2c98..b5b9049a08f2d6e29fc5ee7feb5d1818b52c72a7 100644 (file)
--- a/deal.II/include/deal.II/numerics/error_estimator.h
+++ b/deal.II/include/deal.II/numerics/error_estimator.h
@@ -36,18 +36,19 @@ namespace hp
 
 
 /**
- *  Implementation of the error estimator by Kelly, Gago, Zienkiewicz
- *  and Babuska.  This error estimator tries to approximate the error
+ *  Implementation of the error indicator by Kelly, Gago, Zienkiewicz
+ *  and Babuska.  This error indicator tries to approximate the error
  *  per cell by integration of the jump of the gradient of the
  *  solution along the faces of each cell.  It can be understood as a
  *  gradient recovery estimator; see the survey of Ainsworth for a
  *  complete discussion.
  *
- *  It seem as if this error estimator should only be valid for linear trial
- *  spaces, and there are indications that for higher order trial spaces the
- *  integrals computed here show superconvergence properties, i.e. they tend
- *  to zero faster than the error itself, thus ruling out the values as error
- *  indicators.
+ *  @note In spite of the name, this is not truly an a posteriori
+ *  error estimator, even if applied to the Poisson problem only. It
+ *  gives good hints for mesh refinement, but the estimate is not to
+ *  be trusted. For higher order trial spaces the integrals computed
+ *  here tend to zero faster than the error itself, thus ruling out
+ *  the values as error estimators.
  *
  *  The error estimator really only estimates the error for the generalized
  *  Poisson equation $-\nabla\cdot a(x) \nabla u = f$ with either Dirichlet