Poisson equation, thanks to G. Sadaka
$$ \begin{array}{rcll} -\Delta u & =& f & \mbox{on } \Omega=(0,1)^2\\ u&=& g &\mbox{on } \partial \Omega \end{array} $$
download example: Sadaka_Poisson.edp or return to 2D examples
verbosity=0.;
real Dx=.01,Dy=.01;
mesh Th=square(floor(1./Dx),floor(1./Dy));
fespace Vh(Th,P1);
Vh uh,vh;
func f = 1.;
func g = 0.;
macro Grad(u)[dx(u),dy(u)]//
solve Poisson(uh,vh) = int2d(Th)(Grad(uh)'*Grad(vh))
- int2d(Th)( f*vh) + on(1,2,3,4,uh=g) ;
plot(uh,dim=2,fill=true,value=true,boundary=false);