From 04302cf1181177f0d52191826707d086f0521358 Mon Sep 17 00:00:00 2001 From: Wolfgang Bangerth Date: Fri, 23 Aug 2019 10:13:14 -0600 Subject: [PATCH] Show a VTK-based visualization in step-3, and link to video lectures. --- examples/step-3/doc/results.dox | 60 +++++++++++++-------------------- 1 file changed, 23 insertions(+), 37 deletions(-) diff --git a/examples/step-3/doc/results.dox b/examples/step-3/doc/results.dox index 8318773512..394f50335d 100644 --- a/examples/step-3/doc/results.dox +++ b/examples/step-3/doc/results.dox @@ -19,49 +19,35 @@ sometimes useful for debugging purposes, but often clutters up the screen display. Apart from the output shown above, the program generated the file -solution.gpl, which is in GNUPLOT format. It can be -viewed as follows: invoke GNUPLOT and enter the following sequence of -commands at its prompt: -@code -examples/\step-3> gnuplot - - G N U P L O T - Version 3.7 patchlevel 3 - last modified Thu Dec 12 13:00:00 GMT 2002 - System: Linux 2.6.11.4-21.10-default - - Copyright(C) 1986 - 1993, 1998 - 2002 - Thomas Williams, Colin Kelley and many others - - Type `help` to access the on-line reference manual - The gnuplot FAQ is available from - http://www.gnuplot.info/gnuplot-faq.html - - Send comments and requests for help to - Send bugs, suggestions and mods to - - -Terminal type set to 'x11' -gnuplot> set style data lines -gnuplot> splot "solution.gpl" -@endcode -This produces the picture of the solution below left. Alternatively, -you can order GNUPLOT to do some hidden line removal by the command -@code -gnuplot> set hidden3d -@endcode -to get the result at the right: - +solution.vtk, which is in the VTK format that is widely +used by many visualization programs today -- including the two +heavy-weights Visit and +Paraview that are the most +commonly used programs for this purpose today. + +Using Visit, it is not very difficult to generate a picture of the +solution like this: -
- - - + Visualization of the solution of step-3
+It shows both the solution and the mesh, elevated above the $x$-$y$ plane +based on the value of the solution at each point. Of course the solution +here is not particularly exciting, but that is a result of both what the +Laplace equation represents and the right hand side $f(\mathbf x)=1$ we +have chosen for this program: The Laplace equation describes (among many +other uses) the vertical deformation of a membrane subject to an external +(also vertical) force. In the current example, the membrane's borders +are clamped to a square frame with no vertical variation; a constant +force density will therefore intuitively lead to a membrane that +simply bulges upward -- like the one shown above. + +Visit and Paraview both allow playing with various kinds of visualizations +of the solution. Several video lectures show how to use these programs. +@dealiiVideoLectureSeeAlso{11,32} -- 2.39.5