what is the error "must return a column vector."

function dydt = rhs5(~,y,I)
    ksyn=0.025;
    kdeg1=0.25;
    kdeg2=0.01;
    kCdc_plus=3;
    kCdc_minus=1.5;
    kP_plus=1;
    kP_minus=0.5;
    Kmd=0.02;
    Kmc=0.5;
    Km1=0.005;
    Km2=0.005;
    Km3=0.005;
    Km4=0.005;
    
    dydt=zeros(1,1);
    
    dydt(I.C)=ksyn-kdeg1*y(I.P)*y(I.C)/(Kmd+y(I.C))-kdeg2*y(I.C);
    dydt(I.Cdc)=(kCdc_plus)*(y(I.C)/(Kmc+y(I.C)))*((1-y(I.Cdc))/(Km1+(1-y(I.Cdc))))-(kCdc_minus)*(y(I.Cdc)/(Km2+y(I.Cdc)));
    dydt(I.P)=(kP_plus)*y(I.Cdc)*((1-y(I.P))/(Km3+(1-y(I.P))))-(kP_minus)*(y(I.P)/Km4+y(I.P));
   
end

[times,ys] = ode45(@(t,y)rhs5(t,y,I),tspan,y0,options);
Error using odearguments (line 93)
@(T,Y)RHS5(T,Y,I) must return a column vector.

Error in ode45 (line 115)
  odearguments(FcnHandlesUsed, solver_name, ode, tspan, y0, options, varargin);

why the error happened to my code??

Answer 1

[Star Strider]

The ODE function must return a column vector. I have no idea what ‘I’ is, however defining it as I do here, the code runs without error.

Try this:

function dydt = rhs5(~,y,I)
    ksyn=0.025;
    kdeg1=0.25;
    kdeg2=0.01;
    kCdc_plus=3;
    kCdc_minus=1.5;
    kP_plus=1;
    kP_minus=0.5;
    Kmd=0.02;
    Kmc=0.5;
    Km1=0.005;
    Km2=0.005;
    Km3=0.005;
    Km4=0.005;
    
    dydt=zeros(3,1);
    
    dydt(I.C)=ksyn-kdeg1*y(I.P)*y(I.C)/(Kmd+y(I.C))-kdeg2*y(I.C);
    dydt(I.Cdc)=(kCdc_plus)*(y(I.C)/(Kmc+y(I.C)))*((1-y(I.Cdc))/(Km1+(1-y(I.Cdc))))-(kCdc_minus)*(y(I.Cdc)/(Km2+y(I.Cdc)));
    dydt(I.P)=(kP_plus)*y(I.Cdc)*((1-y(I.P))/(Km3+(1-y(I.P))))-(kP_minus)*(y(I.P)/Km4+y(I.P));
   
end
I = struct('C',1, 'Cdc',2, 'P',3);                              % Create ‘I’
tspan = linspace(0, 1, 10);
y0 = rand(3,1);
[times,ys] = ode45(@(t,y)rhs5(t,y,I),tspan,y0);

figure
plot(times, ys)
grid
legend(fieldnames(I))

.

[jaeug choi]

ahhh! I forgot to fix zeros 1 to 3..!! thanks!

[Star Strider]

My pleasure!

If my Answer helped you solve your problem, please Accept it!

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