[cig-commits] [commit] master: Add a picture to show what an option does. (52abd21)

[cig_noreply at geodynamics.org]

Repository : https://github.com/geodynamics/aspect

On branch  : master
Link       : https://github.com/geodynamics/aspect/compare/5355d1f99396cc686dd0d7b235c54b62a1f4926d...0560cceebc645dd3dbd1ee0d9276248965105b05

>---------------------------------------------------------------

commit 52abd21092761875b8752929018f0b3ae1ab636f
Author: Wolfgang Bangerth <bangerth at math.tamu.edu>
Date:   Mon Sep 15 15:52:47 2014 -0500

    Add a picture to show what an option does.


>---------------------------------------------------------------

52abd21092761875b8752929018f0b3ae1ab636f
 doc/manual/viz/parameters/build-patches.png | Bin 0 -> 147809 bytes
 source/postprocess/visualization.cc         |  28 +++++++++++++++++++++++++++-
 2 files changed, 27 insertions(+), 1 deletion(-)

diff --git a/doc/manual/viz/parameters/build-patches.png b/doc/manual/viz/parameters/build-patches.png
new file mode 100644
index 0000000..5ed2763
Binary files /dev/null and b/doc/manual/viz/parameters/build-patches.png differ
diff --git a/source/postprocess/visualization.cc b/source/postprocess/visualization.cc
index 7dc6575..6f30a0f 100644
--- a/source/postprocess/visualization.cc
+++ b/source/postprocess/visualization.cc
@@ -651,7 +651,33 @@ namespace aspect
                              "of the actual solution field. Activating this option increases "
                              "the spatial resolution in each dimension by a factor equal "
                              "to the polynomial degree used for the velocity finite element "
-                             "(usually 2).");
+                             "(usually 2). In other words, instead of showing one quadrilateral "
+                             "or hexahedron in the visualization per cell on which \\aspect{} "
+                             "computes, it shows multiple (for quadratic elements, it will "
+                             "describe each cell of the mesh on which we compute as "
+                             "$2\\times 2$ or $2\\times 2\\times 2$ cells in 2d and 3d, "
+                             "respectively; correspondingly more subdivisions are used if "
+                             "you use cubic, quartic, or even higher order elements for the "
+                             "velocity)."
+                             "\n\n"
+                             "The effect of using this option can be seen in the following "
+                             "picture showing a variation of the output produced with the "
+                             "input files from Section~\\ref{sec:shell-simple-2d}:"
+                             "\n\n"
+                             "\\begin{center}"
+                             "  \\includegraphics[width=0.5\\textwidth]{viz/parameters/build-patches}"
+                             "\\end{center}"
+                             "Here, the left picture shows one visualization cell per "
+                             "computational cell (i.e., the option is switch off), and the "
+                             "right picture shows the same simulation with the option switched "
+                             "off. The images show the same data, demonstrating that interpolating "
+                             "the solution onto bilinear shape functions as is commonly done in "
+                             "visualizing data loses information."
+                             "\n\n"
+                             "Of course, activating this option also greatly increases the amount of "
+                             "data \\aspect{} will write to disk: approximately by a factor of 4 in 2d, "
+                             "and a factor of 8 in 3d, when using quadratic elements for the velocity, "
+                             "and correspondingly more for even higher order elements.");
 
           // finally also construct a string for Patterns::MultipleSelection that
           // contains the names of all registered visualization postprocessors