plot-fb-p3.edp

FreeFem++可以生成高质量的有限元网格。可以用于流体力学

load "Element_P3"
mesh Th=square(1,1);
plot(Th,wait=1);
mesh th=square(150,150);
fespace Vh(Th,P3);
fespace Wh(th,P1);
func p9=x*x*x+2*y*y*y+3*x*x*y+4*x*y*y+5*x*x+6*x*y+7*y*y+8*x+9*y+10;
func p9x=3 * x * x + 6 * x * y + 4 * y * y + 10 * x + 6 * y + 8;
func p9y=6 * y * y + 3 * x * x + 8 * x * y + 6 * x + 14 * y + 9;
func p9yy= 12 * y + 8 * x + 14;
func p9xx=6 * x + 6 * y + 10;
func p9xy=6 * x + 8 * y + 6;



Vh vi=p9;

cout << " 0.2,0.1 : " << vi(0.2,0.1)<<  " " << p9(0.2,0.1) << endl;
cout << " 0.2,0.1 : " << dx(vi)(0.2,0.1)<<  " " << p9x(0.2,0.1) << endl;
cout << " 0.2,0.1 : " << dy(vi)(0.2,0.1)<<  " " << p9y(0.2,0.1) << endl;
cout << " 0.2,0.1 : " << dxx(vi)(0.2,0.1)<<  " " << p9xx(0.2,0.1) << endl;
cout << " 0.2,0.1 : " << dyy(vi)(0.2,0.1)<<  " " << p9yy(0.2,0.1) << endl;
cout << " 0.2,0.1 : " << dxy(vi)(0.2,0.1)<<  " " << p9xy(0.2,0.1) << endl;
vi=0;
if(!NoUseOfWait)
  for (int i=0;i<min(vi[].n,5);++i)
 {
    vi[][i]=1;
    vi;
    plot(vi,wait=0,cmm=" v"+i);
    if(0)
      { savemesh(th,"mm",[x,y,vi*0.5]);   //save *.points and *.faces file for medit
      exec("ffmedit mm");
      exec(" rm mm.faces mm.points");
      }	
    vi=vi;	
    cout << i << " vi = "<< vi[]<<endl;
    vi[]=0;
    
 }