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mesh Th=square(10,10);
fespace Vh(Th,P1); // P1 FE space
Vh uh,vh,u; // unkown and test function.
func f=1; // right hand side function
func g=0.; // boundary condition function
problem laplace(uh,vh,solver=GMRES,tgv=1e5) = // definion of the problem
- int2d(Th)( -dx(uh)*dx(vh) - dy(uh)*dy(vh) ) // bilinear form
- int1d(Th,1)( -uh*vh)
- int1d(Th,1)( vh)
- int2d(Th)( f*vh ) // linear form
+ on(2,3,4,uh=g) ; // boundary condition form
problem laplacep(uh,vh,solver=CG,tgv=1e5) = // definion of the problem
int2d(Th)( dx(uh)*dx(vh) + dy(uh)*dy(vh) ) // bilinear form
+ int1d(Th,1)( uh*vh)
+ int1d(Th,1)( - vh)
+ int2d(Th)( -f*vh ) // linear form
+ on(2,3,4,uh=g) ; // boundary condition form
laplace; // solve the problem plot(uh); // to see the result
u=uh;
laplacep; // solve the problem plot(uh); // to see the result
plot(uh,u,value=true);
u[] -= uh[];
cout << "Diff min = "<< u[].min << " max=" << u[].max << endl ;
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