/usr/share/doc/freefem-examples/accous.pde is in freefem-examples 3.5.8-5.1ubuntu1.
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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 | /* -*- Mode: pde -*- */
complex;
border(1,0,1,20){ x:=5; y:=1+2*t};
border(1,0,1,20){ x:=5-2*t; y:=3};
border(1,0,1,20){ x:=3-2*t; y:=3-2*t};
border(1,0,1,10){ x:=1-t; y:=1};
border(2,0,1,10){ x:=0; y:=1-t};
border(1,0,1,10){ x:=t; y:=0};
border(1,0,1,20){ x:=1+4*t; y:=t};
buildmesh(1000);
c=I*0.895;
f=exp(-10*((x-0.5)*(x-0.5)+(y-0.5)*(y-0.5)));
g=exp(I*(0.7*x+0.7*y));
solve(u){
onbdy(1) id(u)*c+dnu(u)=0;
onbdy(2) u=g;
pde(u) laplace(u)+id(u)*0.8 = 0;
};
plot(u);
imu=Im(u);
plot(imu);
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