wzpointtest.html

有限元学习研究用源代码(老外的),供科研人员参考

<TITLE>WZ 1.0 - Points</TITLE>

<H1>Points</H1>

 <P>Points are often used: in WZ for the definition of a wzeometry,
in IBG for refinement criteria.

<PRE>
#include "<A HREF="wzpoint.hxx">wzpoint.hxx</A>"
</PRE>

 <P>An interesting property of the class <B>wzPoint</B> is that after
construction only the coordinates of the point are defined, but the
point itself is still invalid.  To make the point valid, the <A
HREF="wzsegmenttest.html">segment</A> of the point should be defined.

<PRE>
void test()
{
  wzPoint p0,p1(0.1),p2(0.1,0,2),p3(0.1,0.2,0.3);
  now(p0.invalid()); now(p1.invalid()); now(p2.invalid()); now(p3.invalid());
  p0.segment()=wzRegion(2);
  p1.segment()=wzFace(1);
  p2.segment()=wzEdge(1);
  p3.segment()=wzVertex(1);
  now(p0.valid());  now(p0.inRegion());  now(p0.region()==2); now(p0.codim()==0);
  now(p1.valid());  now(p1.onFace());    now(p1.face()==1);   now(p1.codim()==1);
  now(p2.valid());  now(p2.onEdge());    now(p2.edge()==1);   now(p2.codim()==2);
  now(p3.valid());  now(p3.isVertex());  now(p3.vertex()==1); now(p3.codim()==3);
</PRE>

 <P>The reason for this choice was that this definition is the result
of a nontrivial operation - geometry description.

<H3>Coordinates</H3>

 <P>For every point, <B>wzPoint::Dim</B> coordinates are defined.
There are various syntactic possibilities to access them:

<PRE>
  p0.x() = 0.1; now(p0[0]==0.1); now(p0.X[0]==0.1);
  p0.y() = 0.1; now(p0[1]==0.1); now(p0.X[1]==0.1);
  p0.z() = 0.1; now(p0[2]==0.1); now(p0.X[2]==0.1);
</PRE>

 <P>There are also <B>wzPoint::DimFloat</B> additional floating point
values. Again, there are various syntactic access possibilities:

<PRE>
  p0.f() = 0.1; now(p0.f(0)==0.1);
  if(p0.floatValues()&gt;2){
    p0.g() = 0.2; now(p0.f(1)==0.2);
    p0.h() = 0.3; now(p0.f(2)==0.3);
  }
</PRE>

 <P>There are also <B>wzPoint::DimIndex</B> additional index
values. Again, there are various syntactic access possibilities:

<PRE>
  p0.i() = 1; now(p0.i(0)==1);
  if(p0.indexValues()&gt;2){
    p0.j() = 2; now(p0.i(1)==2);
    p0.k() = 2; now(p0.i(2)==2);
  }
</PRE>

<A NAME="baddim"> <hr></A>
<H3>About the dimensions</H3>

 <P>The standard values of the parameters (initialized in <A
HREF="wzpoint.cxx"> wzpoint.cxx</A> are the constants
<B>wzPointDim</B>, <B>wzPointDimFloat</B>, <B>wzPointDimIndex</B>
defined in <A HREF="wzpoint.hxx"> wzpoint.hxx</A>.  They may be
changed during runtime with <B>setSpaceDimension</B>,
<B>setFloatValues</B> and <B>setIndexValues</B>.  But they should not
become greater than the constants:

<PRE>
  p0.setSpaceDimension(2);
  p0.setFloatValues(0);
  p0.setIndexValues(0);
  try{
	p0.setSpaceDimension(4);	should_fail();
	p0.setFloatValues(2);		should_fail();
	p0.setIndexValues(2);		should_fail();
 }catch(wzError e){;}
</PRE>

 <P>The designed purpose of making them smaller is to make some
functions like copy-operations and scalar products faster.  To allow
more function values, you should modify the constants
<B>wzPointDim</B>, <B>wzPointDimFloat</B>, <B>wzPointDimIndex</B>
defined in <A HREF="wzpoint.hxx"> wzpoint.hxx</A> and recompile the
whole package.

<PRE>
}
</PRE>