schwarz-overlap.edp

FreeFem++可以生成高质量的有限元网格。可以用于流体力学

real pi=4*atan(1);
int inside = 2;
int outside = 1;
border a(t=1,2){x=t;y=0;label=outside;};
border b(t=0,1){x=2;y=t;label=outside;};
border c(t=2,0){x=t ;y=1;label=outside;};
border d(t=1,0){x = 1-t; y = t;label=inside;};
border e(t=0, pi/2){ x= cos(t); y = sin(t);label=inside;};
border e1(t=pi/2, 2*pi){ x= cos(t); y = sin(t);label=outside;}; 
int n=4;
mesh th = buildmesh( a(5*n) + b(5*n) + c(10*n) + d(5*n));
mesh TH = buildmesh ( e(5*n) + e1(25*n) );
plot(th,TH,ps="schwarz-th.eps");
fespace vh(th,P1);
fespace VH(TH,P1);
vh u=0,v; VH U,V;
int i=0;

problem PB(U,V,init=i,solver=Cholesky) = 
    int2d(TH)( dx(U)*dx(V)+dy(U)*dy(V) )
  + int2d(TH)( -V) + on(inside,U = u)  +    on(outside,U= 0 ) ;
problem pb(u,v,init=i,solver=Cholesky) = 
    int2d(th)( dx(u)*dx(v)+dy(u)*dy(v) )
  + int2d(th)( -v) + on(inside ,u = U) +    on(outside,u = 0 ) ;


for ( i=0 ;i< 10; i++) 
{   
   PB; 
   pb;
   if (i==0)      plot(U,u,wait=true,ps="schwarz-u"+i+".eps");
};

plot(U,u,ps="schwarz-u.eps");