How Can I draw zero level set of a function with paraview
 

I have wrote an script in matlab (you can find it in below) that I need to know how can I export that to the paraview for drawing its zero level set. (based on my knowledge it would be a sphere).



clear
clc

N=4;
k=[0:N/2-1 0 -N/2+1:-1];
l=[0:N/2-1 0 -N/2+1:-1];
m=[0:N/2-1 0 -N/2+1:-1];

t=0;
dt=.01;
T=200;
eps=.01; % epsilon in the equation;
Meps=1/eps;
Mv=100;
Ma=100;
r0=1;

phi0=zeros(N,N,N);

tic;
for i=1:N
for j=1:N
for n=1:N
i
j
n

fun1 = @(x,y,z) [cos(pi*(k(i)*x+l(j)*y+m(n)*z))-1i*sin(pi*(k(i)*x+l(j)*y+m(n)*z))].*tanh((r0-sqrt(x.^2 +y.^2 +z.^2 ))/eps);
phi0(i,j,n)=integral3(fun1,-1,1,-1,1,-1,1);
end
end
end
toc;