Define a complicated function

how we define the following function with FF++
f(x,y,0)= 0.5 * v0 * (1+tanh(500 * (R-r(x,y)))), r(x,y) <= R , 0 if r(x,y)>R
where r(x,y)=sqrt{(x-x_0)^2+(y-y_0)^2} and R=\sqrt{x_0/pi}

v0, x_0 and y_0 are real data

Thank you in advance

No difficulty

just see :

testfunc.edp (185 Bytes)

Thank you so much!
Another question please. If we have

mesh Th = square(N,N,[L*x,H*y]);
fespace Vh(Th,P1);

then we must interpolate the function f with

Vh f;

Just write

 f= sin(x)*cos(y); 

where f is the interpolation of function f : ( x,y) → sin(x)*cos(y)