adapt.edp

FreeFem++可以生成高质量的有限元网格。可以用于流体力学

border a(t=0,1.0){x=t;   y=0;  label=1;};// comment 
border b(t=0,0.5){x=1;   y=t;  label=2;};
border c(t=0,0.5){x=1-t; y=0.5;label=3;};
border d(t=0.5,1){x=0.5; y=t;  label=4;};
border e(t=0.5,1){x=1-t; y=1;  label=5;};
border f(t=0.0,1){x=0;   y=1-t;label=6;};
mesh Th = buildmesh (a(6) + b(4) + c(4) +d(4) + e(4) + f(6));
savemesh(Th,"th.msh");
fespace Vh(Th,P1);
Vh u,v;
real error=0.01;
problem Probem1(u,v,solver=CG,eps=1.0e-6) =
    int2d(Th,qforder=2)( u*v*1.0e-10+  dx(u)*dx(v) + dy(u)*dy(v)) 
  + int2d(Th,qforder=2)( (x-y)*v);
int i;
for (i=0;i< 4;i++)
{   
  Probem1; 
   cout << u[].min << " " << u[].max << endl; 
   plot(u,wait=1);
   Th=adaptmesh(Th,u,err=error);
   plot(Th,wait=1);
  u=u;
  error = error/2;
} ;