How do I draw zero level set of a function in matlab? (Based on my knowledge, it would be a sphere)

I attached my script here.

clear

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);

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

Answer 1

[Steven Lord]

Use an isosurface as shown on this documentation page.