# Plot in 3d with .vtu (visualization with paraview)

Hi

i have to plot the Following function:

q(x/eps,y/eps,z/eps)=1 if (x/eps,y/eps,z/eps) \in B_{\delta}+ Z^3, else 0.

where B_{delta} is the ball with radius

\delta= ((3/4)(1/(wpi)))^{1/3}

we choise eps=0.1 and w=2000.

The problem is that in .vtu we Don’t ditingue the ball when q=1 to the rest when q=0.

I search in the doc but i Don’t find how we save .vtu in 3d (i choice 3d in paraview). So there is an solution?

And the image after copilation Don’t show the ball.

Thank you in advance to the help. There is the code:

’ ’ ’ freefem
defaulttoUMFPACK64();

verbosity=1;

func real q (real t, real s, real c,real w) {
real t1 = t - rint(t);
real s1 = s - rint(s);
real delta= ((3./4.)(1./(piw)))^(1/3);
if ( square(s1)+square(t1)+square(c1) <= square(delta))
return 1;
else
return 0.0;
};
real eps=0.2, w=2000.;

mesh3 Th=cube(30,30,30);
fespace Wh(Th,P2,periodic=[[1,x,z],[3,x,z],[2,y,z],[4,y,z],[5,x,y],[6,x,y]]);
Wh uplot;
int[int] Order= ;

uplot=q(x/eps,y/eps,z/eps,w);
plot(uplot,wait=1,dim=3);
savevtk(“q.vtu”,Th,uplot,dataname=“qdelta”, order=Order);

Kind regards

Hi,

Sorry I cannot understand the problem clearly, but if your problem is you cannot produce any result out of this code, the reason is you forgot to put a dot in the formula that calculates radius of the balls. It should be changed to this:

real delta = ((3./4.) *(1./(pi* w)))^(1./3);


"1/3" equals 0, while "1./3" is 0.333.

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