HOW TO SAVE MATRIX VALUES IN A DOUBLE FOR LOOP

This is my code, i need to save every value generated in the loop, x_pto is a 1x2701 matrix and x is a 289x31 matrix, what i want to do is subtract X each x_pto and save all the values generated i (East,North,Up) i know they are going to be huge matrix but is for my final proyect i need to know how to save that, Could u help me please????!!

i=1;  
   for  lat=pi/2:-pi/36:-pi/2
     for  lon=pi:-pi/36:-pi;  
            East=-sin(lon).*(x-x_pto(:,i))+cos(lon).*(y-y_pto(:,i));
            North=-sin(lat).*cos(lon).*(x-x_pto(:,i))-sin(lat).*sin(lon).*(y-y_pto(:,i))+cos(lat).*(z-z_pto(:,i));
            Up=cos(lat).*cos(lon).*(x-x_pto(:,i))+cos(lat).*sin(lon).*(y-y_pto(:,i))+sin(lat).*(z-z_pto(:,i));

              i=i+1;
       end    
     end