MATLAB: Is the ODE solver saying not enough input arguments

differential equationsmodelingode

In this program I am modeling the cell cycle with three differential equations. I am trying to output all three variables C, M and X to a graph, but I am missing something. Here's the code:
function Cellcycle= Cellcycle (~,~,~,~,~,~,~,~,~,~,~,~,~,~,~,~,~,~,~)
K1 = 0.005;
K2 = 0.005;
K3 = 0.005;
K4 = 0.005;
Kc = 0.5;
Kd = 0.02;
kd = 0.01;
V2 = 1.5;
V4 = 0.5;
vd = 0.25;
VM1 = 3;
VM3 = 1;
C = 0.01;
M = 0.01;
X = 0.01;
dC= 0.025-vd*X*(C/(Kd+C)) - kd*C;
dM = VM1*(C/(Kc+C))*((1-M)/(K1+(1-M))) - V2*(M/(K2+M));
dX = M*VM3*((1-X)/(K3+(1-X))) - V4*(X/(K4+X));
Cellcycle= [dC dM dX];
[~,~,~,~,~,~,~,~,~,~,~,~,~,~,~,~] = ode45('Cellcycle',ode45,[0 10],[.01 .01 .01]);
plot(dC,dM,dX);
end

Best Answer

Note that you are ignoring the ode inputs, so your calls are always going to return the same thing, with a rather boring output as a result. I have taken the liberty of guessing what you are trying to do and changing the code appropriately
function Cellcycle_driver
  [t,y] = ode45(@Cellcycle, [0 10], [.01 .01 .01]);
  dC = y(:,1);
  dM = y(:,2);
  dX = y(:,3);
  plot(t, dC, 'g', t, dM, 'b', t, dX, 'r');
  legend({'dC', 'dM', 'dX'});
function dy = Cellcycle(t, y)
  K1 = 0.005;
  K2 = 0.005;
  K3 = 0.005;
  K4 = 0.005;
  Kc = 0.5;
  Kd = 0.02;
  kd = 0.01;
  V2 = 1.5;
  V4 = 0.5;
  vd = 0.25;
  VM1 = 3;
  VM3 = 1;
  % C = 0.01;
  % M = 0.01;
  % X = 0.01;
  C = y(1):
  M = y(2);
  X = y(3);
    dC= 0.025-vd*X*(C/(Kd+C)) - kd*C;
    dM = VM1*(C/(Kc+C))*((1-M)/(K1+(1-M))) - V2*(M/(K2+M));
    dX = M*VM3*((1-X)/(K3+(1-X))) - V4*(X/(K4+X));
    dy = [dC; dM; dX];
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