p2b.edp

FreeFem++可以生成高质量的有限元网格。可以用于流体力学

mesh Th=square(1,1,[-y+1,x]);
plot(Th,wait=1);
mesh th=square(10,10);
fespace Wh(Th,P2b);
fespace Vh(Th,P2);
fespace Zh(th,P2);
func f=x*y*(1-x-y)+x*2+y*x+6*y;
func fb=x*y*(1-x-y);
Wh u=f;
Vh v=f;

cout << u(1./3,1./3) << endl;
cout << v(1./3,1./3) << endl;
cout << f(1./3,1./3) << endl;
Zh w=u-v;
cout << (u-v)(1./3,1./3) <<" == " << fb(1./3,1./3) << endl;
cout << (u-v)(1./4,1./3) <<" == " << fb(1./4,1./3) << endl;
plot(Th,w,wait=1,value=1);