From 49fc741eead96d5beafdf63bb065c85ab4a209e1 Mon Sep 17 00:00:00 2001
From: Wolfgang Bangerth <bangerth@colostate.edu>
Date: Thu, 22 Jun 2023 10:07:38 -0600
Subject: [PATCH] Warn about the use of higher order output when using Visit.

---
 examples/step-11/step-11.cc | 7 +++++++
 examples/step-44/step-44.cc | 7 +++++++
 examples/step-65/step-65.cc | 7 +++++++
 examples/step-67/step-67.cc | 7 +++++++
 4 files changed, 28 insertions(+)

diff --git a/examples/step-11/step-11.cc b/examples/step-11/step-11.cc
index 4995c30503..ecaab94132 100644
--- a/examples/step-11/step-11.cc
+++ b/examples/step-11/step-11.cc
@@ -409,6 +409,13 @@ namespace Step11
   // class only prints curved faces for <i>boundary</i> cells by default, so we
   // need to ensure that also inner cells are printed in a curved representation
   // via the mapping.
+  //
+  // @note As of 2023, Visit 3.3.3 can still not deal with higher-order cells.
+  //   Rather, it simply reports that there is no data to show. To view the
+  //   results of this program with Visit, you will want to comment out the
+  //   line that sets `flags.write_higher_order_cells = true;`. On the other
+  //   hand, Paraview is able to understand VTU files with higher order cells
+  //   just fine.
   template <int dim>
   void LaplaceProblem<dim>::write_high_order_mesh(const unsigned cycle)
   {
diff --git a/examples/step-44/step-44.cc b/examples/step-44/step-44.cc
index 056c1a9ea7..28d77b65c8 100644
--- a/examples/step-44/step-44.cc
+++ b/examples/step-44/step-44.cc
@@ -3179,6 +3179,13 @@ namespace Step44
   // Here we present how the results are written to file to be viewed
   // using ParaView or VisIt. The method is similar to that shown in previous
   // tutorials so will not be discussed in detail.
+  //
+  // @note As of 2023, Visit 3.3.3 can still not deal with higher-order cells.
+  //   Rather, it simply reports that there is no data to show. To view the
+  //   results of this program with Visit, you will want to comment out the
+  //   line that sets `output_flags.write_higher_order_cells = true;`. On the
+  //   other hand, Paraview is able to understand VTU files with higher order
+  //   cells just fine.
   template <int dim>
   void Solid<dim>::output_results() const
   {
diff --git a/examples/step-65/step-65.cc b/examples/step-65/step-65.cc
index c237368655..bb62d694a9 100644
--- a/examples/step-65/step-65.cc
+++ b/examples/step-65/step-65.cc
@@ -476,6 +476,13 @@ namespace Step65
   // curved faces for <i>boundary</i> cells by default, so we need to ensure
   // that also inner cells are printed in a curved representation via the
   // mapping.
+  //
+  // @note As of 2023, Visit 3.3.3 can still not deal with higher-order cells.
+  //   Rather, it simply reports that there is no data to show. To view the
+  //   results of this program with Visit, you will want to comment out the
+  //   line that sets `flags.write_higher_order_cells = true;`. On the other
+  //   hand, Paraview is able to understand VTU files with higher order cells
+  //   just fine.
   template <int dim>
   void PoissonProblem<dim>::postprocess(const Mapping<dim> &mapping)
   {
diff --git a/examples/step-67/step-67.cc b/examples/step-67/step-67.cc
index 1df2108c75..0e13d851f9 100644
--- a/examples/step-67/step-67.cc
+++ b/examples/step-67/step-67.cc
@@ -2081,6 +2081,13 @@ namespace Euler_DG
   // ignoring the (wrong) values in other entries. The fact that every process
   // submits a vector in which the correct subset of entries is correct is all
   // that is necessary.
+  //
+  // @note As of 2023, Visit 3.3.3 can still not deal with higher-order cells.
+  //   Rather, it simply reports that there is no data to show. To view the
+  //   results of this program with Visit, you will want to comment out the
+  //   line that sets `flags.write_higher_order_cells = true;`. On the other
+  //   hand, Paraview is able to understand VTU files with higher order cells
+  //   just fine.
   template <int dim>
   void EulerProblem<dim>::output_results(const unsigned int result_number)
   {
-- 
2.39.5