I am using ode45 to solve a function describing the interaction between tanks in series. I have the variables C_IN and C_OUT specifing if carbon is flowing into or out of a tank at the specific time. If the mass of carbon in tank 1 drops below a lower limit, carbon must flow into tank 1 from tank 2 until a upper limit is reached. A portion of my code is below. The problem is that C_IN and C_out are reverted back to 0 for each iteration of the solver. Therefore instead of increasing to the concentration to the upper limit, C_IN switches back to 0 as soon as the carbon raises above the lower limit. How can I change my logic so that I can either keep my variables the same from the previous iteration of the solver, or otherwise restructure my code to achieve the same reslut?
C_IN = zeros(11, 1);
C_OUT = zeros(11, 1);
if x(11+i) < 20
C_IN(i/11) = 1;
C_OUT(i/11 + 1) = 1;
end
if x(11+i) > 30
C_IN(i/11) = 0;
C_OUT(i/11 + 1) = 0;
end
Dx(11+i) = C_IN(i/11)*(CF*x(11+i+ci)/T.volume*(1-j6) + j6*4) - C_OUT(i/11)*CF*x(11+i)/T.volume;
