Create a circle in the matrix with zeros

Hi!

I have a Matrix D=onse(N,N).

I would like to make a circle with radius R at the center at (i0,j0) with filled zeros.

I wrote something like that but it takes so long time in my sub-loop to calculate it. Do you have a better idea how can we make such "0" circle inside the matrix?

for i=1:N

for j=1:N

if ((i-i0)^2+(j-j0)^2)<(R^2)

D(i,j)=0;

end

end

end

Thank you for your help!

Answer 1

[Asad (Mehrzad) Khoddam]

% values
N=100;
D=ones(N,N);
i0=10;
j0=20;
R=8;
% filter indise circle
[x,y]=meshgrid(1:N);
D((x-i0).^2+(y-j0).^2<R^2)=0;

[Ivan]

Thank you!