border C(t=0, 2*pi) { x=cos(t); y=sin(t); }; mesh Th = buildmesh(C(100)); fespace Uh(Th,P1dc); Uh v, uold, u = exp(-10*((x-0.3)^2 +(y-0.3)^2)); fespace Xh(Th,P1); Xh b1 = y,b2 = -x; real T = 2*pi; int ts = 125; real alpha=0.5, dt = T/ts; macro nb() (N.x*b1+N.y*b2) // Macro without parameter problem Adual(u,v) = int2d(Th)((u+dt*(b1*dx(u)+b2*dy(u)))*v) + intalledges(Th)((1-nTonEdge)*dt*(v*(alpha*abs(nb)-nb/2)*jump(u))) - int2d(Th)(uold*v); plot(u,wait=true); for ( int n = 0; n