How to perform an operation on a whole column of a matrix?

I have the following code, which uses a variable y=1/r for the ODE. I want to convert back to using r, so thought that after solving with ode45 I could just perform the operation on the whole column and be fine, but it isn't working. Clearly I'm doing this wrong, as it runs fine but gives the complete wrong result.

Here is my code:

for i=1:20
    G=i/20; %Saving that iterates value of G
    [phi,y]=ode45(@(phi,y) odefunction1(phi,y,G), timerange, IC);
    y(:,1)=1/(y(:,1)); %this is where I switch back to using r and save it as an element of the cell z. Issue is, its giving me compeltely the wrong result and returning 0 %everywhere for column 1 of y.
    z{i}=y; 
end

[Dyuman Joshi]

Try using this

y(:,1)=1./y(:,1);

[Gabriel Venter]

Thanks!