ElmerGUI A new preprocessor for Elmer - PowerPoint PPT Presentation

1 / 46

About This Presentation

Title:

ElmerGUI A new preprocessor for Elmer

Description:

... compilation instruction in README.txt: $ qmake project $ qmake ... less README. Mesh generation. ElmerGrid. Built-in mesh generator and mesh manipulation tool ... – PowerPoint PPT presentation

Number of Views:704

Avg rating:3.0/5.0

Slides: 47

Provided by: userA

Category:

more less

Transcript and Presenter's Notes

Title: ElmerGUI A new preprocessor for Elmer

1
ElmerGUI A new pre-processor for Elmer

Mikko Lyly
CSC, Finnish IT Center for Science
Elmer User meeting, 29th May 2008, CSC, Espoo

2
Outline

Backgound
Workflow
Practical example
On input file formats
Excercise
Custom menus

3
Background

Intended to replace ElmerFront
Enhanced mesh generation and mesh manipulation
tools
Enhanced visualization routines (based on OpenGL
and extensions)
Better compatibility with latest Solver
Programmable/customizable GUI
Less dependencies on external libraries
Portability (Linux, Windows, Mac)?
ElmerGUI is not
A CAD program complicated 3D-geometries should
be modelled by separate tools and imported into
ElmerGUI in an appropriate format
A stand-alone-program it needs ElmerSolver and
ElmerPost (the elmer-suite) in path to solve
the problem and visualize the results

4
Prequisites

Libraries
Qt Cross-Platform Application Framework (version
4.2 or higher)?
Qwt - Qt Widgets for Technical Applications
(version 5 or higher)?
Qt4 http//trolltech.com/products/qt/
Qwt5 http//qwt.sourceforge.net/
Licence GPL
Qt4 is pre-installed on most Linux distributions
Binary installation packages available for
Windows and Mac

5
Compilation

Getting the sources
svn co https//elmerfem.svn.sourceforge.net/svnr
oot/elmerfem elmefem
ElmerGUI is located in elmerfem/trunk/misc/Mesh3D
cd elmerfem/trunk/misc/Mesh3D
less LICENCES.txt
Follow the compilation instruction in README.txt
qmake project
qmake
make

6
Mesh generation

Possibility to use the following mesh generators
Tetgen (libtet compiled as a shared library)?
Netgen (libng compiled as a shared library)?
ElmerGrid (built-in)?
No hard-coded dependencies on external generators
For more information and documentation, see
http//tetgen.berlios.de/
http//www.hpfem.jku.at/netgen/
http//www.csc.fi/elmer

7
Mesh generation

Tetgen (libtet)?
Developed by Hang Si et al. at the Weierstrass
Institute for Applied Analysis and Stochastics
Fast and efficient unstructured tetrahedral mesh
generator
Licenced under the MIT-licence
Not free, but for private, research, and
educational purposes it can be used at no
cost and without further arrangements
Due to the commercial restrictions, libtet is not
included in the binary distribution packages of
Elmer.
The user has to make sure that he has a valid
licence, or right to use the genarator otherwise,
and download /compile the shared library from
source
cd elmerfem/trunk/misc/tetgen_patches
patch lt patch_tetgen.h
g -fPIC -c predicates.cxx
g -fPIC -O -DTETLIBRARY -c tetgen.cxx
g -fPIC -c ElmerAPI.cpp
g -shared predicates.o tetgen.o ElmerAPI.o -o
libtet.so

8
Mesh generation

Netgen (libng)?
NETGEN was developed mainly by Joachim Schöberl
within project grants from the Austrian Science
Fund FWF ( Special Research Project "Numerical
and Symbolic Scientific Computing", Start Project
"hp-FEM) at the Johannes Kepler University Linz.
Significant contributions were made by Johannes
Gerstmayr (STL geometry) Robert Gaisbauer
(OpenCascade interface).
Powerful triangular and tetrahedral mesh
generator
Licenced under LGPL included in the binary
distribution packages of Elmer
Instructions for compiling libng from source can
be found from
cd elmerfem/trunk/misc/netgen_patches
less README

9
Mesh generation

ElmerGrid
Built-in mesh generator and mesh manipulation
tool
Very fast structured 1D/2D/3D-mesh generation
Able to import mesh files in several external
formats

10
Mesh generation

Mesh generator chosen automatically by
input-file-format
STL (stereolitography format) libtet or libng
SMESH (piecewise linear complex) libtet
POLY (like SMESH but less restrictions) - libtet
OFF (Geomview's polyhedral file format) - libtet
PLY (polyhedral file format) - libtet
MESH (Medit's surface mesh file format) - libtet
GRD (elmergrid's native input file) - ElmerGrid
FDNET (Fidap's mesh file format) - ElmerGrid
MSH (Gmesh's file format) - ElmerGrid
MPHTXT (Comsol Multiphysic's mesh file format) -
ElmerGrid
UNV (Ideas' universal file format) ElmerGrid
Elmer's native mesh file format

11
Workflow

ElmerGUI ElmerSolver ElmerPost
ElmerGrid
12
Workflow

Open your input file (example samples/grd/angle3d
.grd)

13
Workflow

Optionally configure mesh generator and remesh

14
Workflow

The values in the config dialog are inherited
from cmd line tools

15
Workflow

Remeshing is perfomed in a separate thread

16
Workflow

Manipulate boundaries Select a boundary by
double clicking and choose divide surface to
split it by sharp edges

17
Workflow

Manipulate boundaries Select boundaries by
holding down the CTRL-key while double clicking.
Choose unify surface to join

18
Workflow

Turn on/off boundary index numbering for
verification

19
Workflow

Define an equation (PDE-system) to solve

20
Workflow

Let us define the heat equation as an example

21
Workflow

The equation can later be activated for
modification from menu

22
Workflow

Similarly, we can next define material properties
and parameters

23
Workflow

Data is given in the General and Heat
equation tabs

24
Workflow

Add body force

25
Workflow

Add boundary conditions

26
Workflow

Generate solver input file (sif)

27
Workflow

Edit the solver input file (if needed)

28
Workflow

Save the model

29
Workflow

Run solver

30
Workflow

Convergence monitor reveals possible problems

31
Workflow

Invoke post processor

32
Workflow

Visualize the results by Elmerpost

33
Workflow

You can alternatively define/edit body properties
by holding down the SHIFT-key and by double
clicking any surface of the body

34
Workflow

Similarly, boundary conditions may be (re)defined
by holding down the ALT-key while double clicking
a boundary

35
Workflow

The SHIFT / ALT functionality may also be
activated from menu

36
Workflow

There are some useful functions available from
menu
View -gt Surface mesh (toggles the visibility of
surface mesh)
View -gt Sharp edges (show the sharp edges
separating boundaries)
View -gt Compass (show coordinates)
View -gt Hide/show selected (toggle the visibility
of current selection)
View -gt Numbering (useful for debugging and
verification of the model)
View -gt Reset model view (clear view)
Model -gt Summary (get an overview of the model)
File -gt Save picture as (save the image in
several formats)
Mesh -gt Terminate (kills the meshing thread, if
blocked)
Run -gt Show convergence (toggles the visibility
of convergece monitor)
Run -gt Kill solver (kills the solver process, if
necessary)
Run -gt Kill postprocessor (kills ElmerPost, if
necessary)

37
Input file formats

SMESH
Part 1 - node list
First line lt of pointsgt ltdimension (must be 3)gt
lt of attributesgt lt of boundary markers (0 or
1)gt
Remaining lines list of pointsltpoint gt ltxgt
ltygt ltzgtattributes boundary marker...
Part 2 - facet list
One line lt of facetsgt ltboundary markers (0 or
1)gt
Following lines list of facets lt of cornersgt
ltcorner 1gt ltcorner 2gt ... ltcorner gt boundary
marker...
Part 3 - hole list
One line lt of holesgt
Following lines list of holeslthole gt ltxgt ltygt
ltzgt...
Part 4 - region attributes list
One line lt of regiongt
Following lines list of region
attributesltregion gt ltxgt ltygt ltzgtltregion
numbergtltregion attributegt...

38
Input file formats

Example (L.smesh)
12 3 0 1
1 0 0 0 1
2 4 0 0 1
3 4 2 0 1
4 2 2 0 1
5 2 6 0 1
6 0 6 0 1
7 0 0 2 1
8 4 0 2 1
9 4 2 2 1
10 2 2 2 1
11 2 6 2 1
12 0 6 2 1
8 1
6 1 2 3 4 5 6 1
6 7 8 9 10 11 12 1
4 1 2 8 7 1
4 2 3 9 8 2

39
Input file formats

The previous smesh-file should produce the
following output

40
Input file formats

Mesh density control by volume constaints (see
tetgens manuals for more details about command
relevant line arguments)

41
Input file formats

It is possible to control the density locally by
mtr-files
Example (L.mtr)
12 1
0.25
0.25
0.25
0.025
0.25
0.25
0.25
0.25
0.25
0.025
0.25
0.25

42
Input file formats

Activate local mesh density control by
introducing argument m

43
Input file formats
44
Input file formats

Examples can be found from
Tetgens site at
http//tetgen.berlios.de/
INRIAs mesh database at
http//www-c.inria.fr/gamma/download/disclaimer.p
hp

45
Customizing the GUI

The menus of ElmerGUI are constructed dynamically
when the process is initiated
Menus are described by edf-files
(elmer-definition-file) which are written in XML
containing problem specific information about
dialog styles and dependencies on model data
The files are located in directory edf (with
respect to ElmerGUI)
An example of customizing the menus can be found
from the course material and from Elmers web site

46
Finally