function must return a column vector

Hi, i am trying to plot some graphs for my my theses but i keep on getting error message..

find attached the code.. please help

function Juve_Model

clc;
%close all 

global NO
%initial condition
Initial1 = [100,30,10,30];
hold on
for i=1:2:10
    Initial=Initial1*i;
    [t,u]=ode45(@hcv4,0:0.5:90, Initial);
    
    subplot(2,2,1)
    grid on
    hold on
    %axis([0 1400 0 1]);
    plot(t,u(:,1),'linewidth',3);
    xlabel('Time (days)')
    ylabel('L')
    %*********************************************
    
    subplot(2,2,2)
    grid on
    hold on
    plot(t,u(:,2),'linewidth',3);
    xlabel('Time (days)')
    ylabel('F_1')
    %********************************************
    
    subplot(2,2,3)
    grid on
    hold on
    plot(t,u(:,3),'linewidth',3);
    xlabel('Time (days)')
    ylabel('F_2')
    %*******************************************
    
    subplot(2,2,4)
    grid on
    hold on
    plot(t,u(:,4),'linewidth',3);
    xlabel('Time (days)')
    ylabel('M')
    
end
NO
end

function dy=hcv4(t,y)
%y=(L, F_1,F_2,M)=(y(1),y(2),y(3),y(4))

global NO
alpha=15; beta=0.1; q=0.3; gamma =0.7;
%beta=0.15; q=0.35; gamma=0.75;
K=1000; mu_L=0.35; d=0.45; mu_F1=0.15; mu_M=0.15; mu_F2=0.5;

% Basic Offspring (Reproduction) Number

NO=alpha*gamma*beta*q/(mu_F2*(mu_F1+gamma)*(beta+mu_L+d));

%Ordinary differential equation
dy(1)=alpha*(1-y(1)/K)*y(3)-(beta+mu_L+d)*y(1);
dy(2)=beta*q*y(1)-(mu_F1+gamma)*y(2);
dy(3)=gamma*y(2)-mu_F2*y(3);
dy(4)=beta*(1-q)*y(1)-mu_M*y(4);
end

Answer 1

[Torsten]

Allocate dy as a column vector before assigning values to it:

%Ordinary differential equation
dy = zeros(4,1);
dy(1)=alpha*(1-y(1)/K)*y(3)-(beta+mu_L+d)*y(1);
dy(2)=beta*q*y(1)-(mu_F1+gamma)*y(2);
dy(3)=gamma*y(2)-mu_F2*y(3);
dy(4)=beta*(1-q)*y(1)-mu_M*y(4);

And why do you need "NO" as a global variable ?

[Musa Abdullahi]

No Reason..

Any better recommendation?

[Torsten]

Any better recommendation?

If you don't need it, I'd delete it.

So problem solved ?

[Musa Abdullahi]

Ok.. Let me try that.

[Musa Abdullahi]

Works Perfectly. Thank you..

what if i want to plot the individual populations?

not subplots

[Torsten]

Juve_Model()

function Juve_Model

clc;
%close all 

%initial condition
Initial1 = [100,30,10,30];
index = 0;
for i=1:2:10
    Initial=Initial1*i;
    [t,u]=ode45(@hcv4,0:0.5:90, Initial);
    index = index + 1;
    T{index} = t;
    U{index} = u;
end
figure(1)
hold on
for i = 1:5
  plot(T{i},U{i}(:,1),'linewidth',3)
end
hold off
grid on
    xlabel('Time (days)')
    ylabel('L')
figure(2)
hold on
for i = 1:5
  plot(T{i},U{i}(:,2),'linewidth',3)
end
hold off
grid on
    xlabel('Time (days)')
    ylabel('F_1')
figure(3)
hold on
for i = 1:5
  plot(T{i},U{i}(:,3),'linewidth',3)
end
hold off
grid on
    xlabel('Time (days)')
    ylabel('F_2')
figure(4)
hold on
for i = 1:5
  plot(T{i},U{i}(:,4),'linewidth',3)
end
hold off
grid on
    xlabel('Time (days)')
    ylabel('M')
end

function dy=hcv4(t,y)
%y=(L, F_1,F_2,M)=(y(1),y(2),y(3),y(4))

alpha=15; beta=0.1; q=0.3; gamma =0.7;
%beta=0.15; q=0.35; gamma=0.75;
K=1000; mu_L=0.35; d=0.45; mu_F1=0.15; mu_M=0.15; mu_F2=0.5;

% Basic Offspring (Reproduction) Number

NO=alpha*gamma*beta*q/(mu_F2*(mu_F1+gamma)*(beta+mu_L+d));

%Ordinary differential equation
dy = zeros(4,1);
dy(1)=alpha*(1-y(1)/K)*y(3)-(beta+mu_L+d)*y(1);
dy(2)=beta*q*y(1)-(mu_F1+gamma)*y(2);
dy(3)=gamma*y(2)-mu_F2*y(3);
dy(4)=beta*(1-q)*y(1)-mu_M*y(4);
end

[Musa Abdullahi]

Thanks alot..