MATLAB: For loop

for loop

I have matrix M(3,3)

I need to solve this equation

for i=1:3

    for j=1:3
        for k=1:3
            bi,j,k=(1/2)*(diff(M(k,j),theta1)+diff(M(k,i),theta1)-diff(M(i,j),theta1))
        end
    end
end

I need to have the answers in form

b111

b112

b121

….

b333

how i can do that thx