mainrefanisotest.html

Delaunay三角形的网格剖分程序

<TITLE>COG 2.1: Anisotropic refinement with a function</TITLE>
<PRE>
#include "<A HREF="coglib.hxx">cog/coglib.hxx</A>"
</PRE>

<H1>Anisotropic Refinement Using Functions</H1>

 <P>In COG, the refinement may be controlled by
 <A HREF="mainfunctiontest.html">functions</A> which define the
maximal distance in each direction around a given node - the
<B>anisotropic refinement function</B>.

 <P>For example, to define the refinement in this picture:
 <P><IMG SRC="refanisotest.gif">
 <P>you can use the following simple function:

<PRE>
wzFloat dx(const wzPoint&amp; p)
{
  return 0.1 + 0.4*(p[0]*p[0]+p[1]*p[1]);
}
wzFloat dy(const wzPoint&amp; p)
{
  return 0.1 + 0.4*((1-p[0])*(1-p[0])+p[1]*p[1]);
}
</PRE>

 <P>There are also a lot of <A HREF="mainfunctiontest.html">other
possibilities to define functions</A>.  Now we define a simple octree
grid generator and define these functions <I>dx, dy</I> on it's
geometry
 <A HREF="mainfunctiontest.html">as usual</A>:

<PRE>
int main()
{
  cogenOctree base = new CogenOctree();
  base-&gt;setBorder(0.0,1.0, 0.0,1.0);
  cogeometry geom0 = base-&gt;geometry();
  wzIndex    px = 0, py = 1;
  cogeometry geom1 = new CogeometryFunctionOnRegions(geom0,dx,px);
  cogeometry geom  = new CogeometryFunctionOnRegions(geom1,dy,py);
</PRE>

 <P>Now we have to create a grid generator which uses the function at
<I>place</I> as the isotropic refinement criterion.  This is done by

<PRE>
  wzIndex dim = 2;
  cogenerator gen;
  gen = new CogenRefinementFunctionAnisotropic(base-&gt;generator(),px,dim);
</PRE>

 <P>What remains is standard:

<PRE>
  wzgrid grid = (*gen)(geom);
  grid-&gt;write("test.sg");
}
</PRE>