sibl

Lesson 07: Dualization Code-Only Workflow

Goals

• Compile the SIBL Mesh Engine source code to an executable. This procedure uses neither Python nor the sibl conda environment.
• Run the executable with a .yml input file
  • without MATLAB, and
  • with MATLAB.

Obtain Source Files

The C++ source code resides at ~/sibl/geo/src/dual/. For this workflow:

• Only *.h and *.cpp files in this directory are required;
• The entire repository is not needed.

Compile Dualization Code

Compile the C++ code to generate an executable.

Linux and Mac operating systems come with a C++ compiler; Windows does not. On a Windows machine you will need to install a C++ compiler. The minimilist approach is to get MinGW (https://osdn.net/projects/mingw/). Once this is installed and you have added the bin folder to your path, you can compile by opening a command prompt in the folder that contains the source and header files.

On a Windows machine, compile at the command prompt. Note, the first option after g++ is -O3 with a capital O and not -03 with a zero 0.

> g++ -O3 -std=c++11 *.cpp -o dual.exe

On a Mac or Linux machine, compile at the command line.

> g++ -O3 -std=c++11 *.cpp -o dual.out

Verify it compiled properly by running the executable with no inputs.

• On a Windows machine, double click the executable file or run at the command prompt by typing dual.exe. It should generate an example .yml file with the inputs you will need to specify to mesh a surface.
• On a Mac or Linux, the file dual.out will be present.

Steps without MATLAB

Generate an input .yml file to specify to the engine what procedures to undertake. For this example, use circle.yml, which uses the boundary definition file circle.txt. Running the executable without any arguments will automatically generate a template .yml file that you can modify.

boundary: circle.txt
boundary_refine: true
bounding_box: [[0,0],[0,0]]
developer_output: true # false gives a mesh .inp file produced without intermediate meshes
output_file: circle
resolution: 0.5
version: 1.1

On a Windows machine, drag the .yml input file on top of the executable - make sure the boundary file has the path specified or exits in the same folder as the executable. This will generate an .INP file, which can be imported into many meshing and FEA applications such as Cubit or Abaqus.

Steps with MATLAB

We are using MATLAB as a wrapper to generate the boundary file and then run the dualization. However, you can simply use the .yml file and the executable to generate the output mesh file. We are also assuming a Windows machine in the following example. If you are on a Mac or Linux, update the paths and executable call.

• Open plotCircleEx.m in the MATLAB editor.
• Update the binpath as necessary for your local folder configuration.
• Run the .m file from the editor or command line.

clear all
close all

%Set path to executable if not working in the same directory
binpath = 'C:\Users\acsokol\sibl\geo\src\dual\bin\';%%%<<<< windows path, modify as needed

%Create circle geometry for this example
th = [0:5:355];
pts = [5*cosd(th)' 5*sind(th)']';
%Write circle geometry to file
fid = fopen(['circle.txt'],'w');
fprintf(fid,'%12.16f  %12.16f\n',pts);
fclose(fid);

%Run executable through Matlab dos command / Can also just drag YML file onto executable or run from command prompt
dos([binpath,'dual.exe circle.yml']); %%%<<<< windows executable extension .exe, modify as needed

n = load('dualnodes');
q = load('dualquads');

figure;
plot(pts(1,:),pts(2,:),'k-','LineWidth',2);hold on;
for qq=1:size(q,1)
   seq = [q(qq,:) q(qq,1)]; %close the loops
   plot(n(seq,2),n(seq,3),'k-')
end
axis equal;
axis off
print(gcf,'-dpng',['circle.png']);

Running the MATLAB script will generate this figure:

Index

Previous: Lesson 06

Next: Lesson 08

This site is open source. Improve this page.