fe.edp

FreeFem++可以生成高质量的有限元网格。可以用于流体力学

//  test all FEspace
verbosity=10;
mesh Th=square(5,5);
verbosity = 10;
cout << " P0 " << endl;
fespace Ph(Th,P0);
cout << " P1 " << endl;
fespace Vh(Th,P1);
cout << " P2 " << endl;
fespace Wh(Th,P2);
cout << " nb of degre of freedom           : " << Wh.ndof << endl;
cout << " nb of degre of freedom / ELEMENT : " << Wh.ndofK << endl;
//*  don't work to day in progresse
{
 int k= 2;
 int kdf= Wh.ndofK ;
cout << " df of element " << k << ":" ;
for (int i=0;i<kdf;i++)
  cout << Wh(k,i) << " ";
 cout << endl;
}
//*/
cout << " P1nc " << endl;
fespace Vnch(Th,P1nc);
Vnch u1nc=x+10*y;
cout << " Interpola P1nc : " << int2d(Th)(square(u1nc-(x+10*y))) << endl;

cout << " P2dc " << endl;
fespace Wdch(Th,P2dc);

cout << " P1dc " << endl;
fespace Vdch(Th,P1dc);
Vdch u1dc=x+10*y;
cout << " Interpola P1dc : " << int2d(Th)(square(u1dc-(x+10*y))) << endl;

Wh w=x*x*y,dxw=2*x*y;

Vdch vdc = dx(w);
Wdch wdc = dx(w)*x;
plot(vdc,dxw,wait=1);
plot(wdc);
Vnch vnc = x*x;
Vh vh = x*x;
Ph p = x*x;

{
func f=x*x+10*y*y+50*x*y;
cout << " P2b " << endl;
fespace Wh2b(Th,P2);
Wh2b vh=f;
cout << " ?? " << vh(0.1,0.4) << " == " << f(0.1,0.4) <<  " diff = " << vh(0.1,0.4) - f(0.1,0.4) <<endl;
assert( abs(vh(0.1,0.4) - f(0.1,0.4)) < 1e-12 );
}