my rand operation is applied correctly, I think but it's not working.

clear
ti = 0;
tf = 10E-3;
tspan=[ti tf];
y0=[1; 1; 0; 1; 1; 0; 1; 1; 0; 1; 1; 0; 1; 1; 0; 0; 0 ; 0; 0; 0]*10E-4;
yita_mn = [0 1 0 0 1; 1 0 1 0 0; 0 1 0 1 0; 0 0 1 0 1; 1 0 0 1 0]*(1E-3);
N = 5;
tp = 5.4E-9;
[T,Y]= ode45(@(t,y) rate_eq(t,y,yita_mn,N),tspan,y0);

Unable to perform assignment because the left and right sides have a different number of elements.

Error in solution>rate_eq (line 42)
dOdt(i) = o(1,:);

Error in solution (line 9)
[T,Y]= ode45(@(t,y) rate_eq(t,y,yita_mn,N),tspan,y0);

Error in odearguments (line 92)
f0 = ode(t0,y0,args{:}); % ODE15I sets args{1} to yp0.

Error in ode45 (line 107)
odearguments(odeIsFuncHandle,odeTreatAsMFile, solver_name, ode, tspan, y0, options, varargin);

% time =T./tp done, because to measure the time in unit of tp 


plot(T./tp,Y(:,16));


function dy = rate_eq(t,y,yita_mn,N)

dy = zeros(4*N,1);
dGdt = zeros(N,1);
dAdt = zeros(N,1);
dOdt = zeros(N,1);

P = 16.7;
a = 0.1;
tc = 230E-6;
tp =5.4E-9;
o = [1 2 32 421 2]*10E2;
k_c = 1/tp;

Gt = y(1:3:3*N-2);
At = y(2:3:3*N-1);
Ot = y(3:3:3*N-0);

%A is the amplitude
%G is the gain
%O is the phase

for i = 1:N
    dGdt(i) = (P - Gt(i).*((abs(At(i)))^2 +1))./tc ; 
    dAdt(i) = (Gt(i)-a).*((At(i))./tp);
    dOdt(i) = o(1,:);  
    for j = 1:N
        dAdt(i) = dAdt(i)+yita_mn(i,j)*k_c*(At(j))*cos(Ot(j)-Ot(i));
        dOdt(i) = dOdt(i)+yita_mn(i,j)*k_c*((At(j)/At(i)))*sin(Ot(j)-Ot(i));
    end
end

dy(1:3:3*N-2) = dGdt;
dy(2:3:3*N-1) = dAdt;
dy(3:3:3*N-0) = dOdt;
dy(16)= dy(6) - dy(3);
dy(17)= dy(9) - dy(6);
dy(18)= dy(12) - dy(6);
dy(19)= dy(15) - dy(12);
dy(20)= dy(3) - dy(15);
end

Answer 1

[Chunru]

Check out the line:

dOdt(i) = o(i); %o(1,:);

ti = 0;
tf = 10E-3;
tspan=[ti tf];
y0=[1; 1; 0; 1; 1; 0; 1; 1; 0; 1; 1; 0; 1; 1; 0; 0; 0 ; 0; 0; 0]*10E-4;
yita_mn = [0 1 0 0 1; 1 0 1 0 0; 0 1 0 1 0; 0 0 1 0 1; 1 0 0 1 0]*(1E-3);
N = 5;
tp = 5.4E-9;


[T,Y]= ode45(@(t,y) rate_eq(t,y,yita_mn,N),tspan,y0);

plot(T./tp,Y(:,16));

function dy = rate_eq(t,y,yita_mn,N)
dy = zeros(4*N,1);
dGdt = zeros(N,1);
dAdt = zeros(N,1);
dOdt = zeros(N,1);
P = 16.7;
a = 0.1;
tc = 230E-6;
tp =5.4E-9;
o = [1 2 32 421 2]*10E2;
k_c = 1/tp;
Gt = y(1:3:3*N-2);
At = y(2:3:3*N-1);
Ot = y(3:3:3*N-0);
%A is the amplitude
%G is the gain
%O is the phase
for i = 1:N
    dGdt(i) = (P - Gt(i).*((abs(At(i)))^2 +1))./tc ; 
    dAdt(i) = (Gt(i)-a).*((At(i))./tp);
    dOdt(i) = o(i);      %o(1,:);  
    for j = 1:N
        dAdt(i) = dAdt(i)+yita_mn(i,j)*k_c*(At(j))*cos(Ot(j)-Ot(i));
        dOdt(i) = dOdt(i)+yita_mn(i,j)*k_c*((At(j)/At(i)))*sin(Ot(j)-Ot(i));
    end
end
dy(1:3:3*N-2) = dGdt;
dy(2:3:3*N-1) = dAdt;
dy(3:3:3*N-0) = dOdt;
dy(16)= dy(6) - dy(3);
dy(17)= dy(9) - dy(6);
dy(18)= dy(12) - dy(6);
dy(19)= dy(15) - dy(12);
dy(20)= dy(3) - dy(15);

end

[SAHIL SAHOO]

clear
ti = 0;
tf = 10E-3;
tspan=[ti tf];
y0=[1; 1; 0; 1; 1; 0; 1; 1; 0; 1; 1; 0; 1; 1; 0; 0; 0 ; 0; 0; 0]*10E-4;
yita_mn = [0 1 0 0 1; 1 0 1 0 0; 0 1 0 1 0; 0 0 1 0 1; 1 0 0 1 0]*(1E-3);
N = 5;
tp = 5.4E-9;


[T,Y]= ode45(@(t,y) rate_eq(t,y,yita_mn,N),tspan,y0);

plot(T./tp,Y(:,20));

function dy = rate_eq(t,y,yita_mn,N)
dy = zeros(4*N,1);
dGdt = zeros(N,1);
dAdt = zeros(N,1);
dOdt = zeros(N,1);
P = 16.7;
a = 0.1;
tc = 230E-6;
tp =5.4E-9;
o = rand(1,5)*10E2
k_c = 1/tp;
Gt = y(1:3:3*N-2);
At = y(2:3:3*N-1);
Ot = y(3:3:3*N-0);
%A is the amplitude
%G is the gain
%O is the phase
for i = 1:N
    dGdt(i) = (P - Gt(i).*((abs(At(i)))^2 +1))./tc ; 
    dAdt(i) = (Gt(i)-a).*((At(i))./tp);
    dOdt(i) = o(1,i);      %o(1,:);  
    for j = 1:N
        dAdt(i) = dAdt(i)+yita_mn(i,j)*k_c*(At(j))*cos(Ot(j)-Ot(i));
        dOdt(i) = dOdt(i)+yita_mn(i,j)*k_c*((At(j)/At(i)))*sin(Ot(j)-Ot(i));
    end
end
dy(1:3:3*N-2) = dGdt;
dy(2:3:3*N-1) = dAdt;
dy(3:3:3*N-0) = dOdt;
dy(16)= dy(6) - dy(3);
dy(17)= dy(9) - dy(6);
dy(18)= dy(12) - dy(6);
dy(19)= dy(15) - dy(12);
dy(20)= dy(3) - dy(15);

end

I have a doubt here, why I'm getting lots of random value, i use rand(1,5) so i should get 1 cross 5 matrix with random value, but i got lots of random value.

[Chunru]

It seems that "o = rand(1,5)*10E2" should be a variable outside of function rate_eq.

ti = 0;
tf = 10E-3;
tspan=[ti tf];
y0=[1; 1; 0; 1; 1; 0; 1; 1; 0; 1; 1; 0; 1; 1; 0; 0; 0 ; 0; 0; 0]*10E-4;
yita_mn = [0 1 0 0 1; 1 0 1 0 0; 0 1 0 1 0; 0 0 1 0 1; 1 0 0 1 0]*(1E-3);
N = 5;

o = rand(1,5)*10E2   % <==============

o = 1×5

999.7924 590.6161 103.2922 271.9314 209.2086

tp = 5.4E-9;
[T,Y]= ode45(@(t,y) rate_eq(t,y,yita_mn,N, o),tspan,y0);
plot(T./tp,Y(:,20));

function dy = rate_eq(t,y,yita_mn,N, o)   % o as parameters
dy = zeros(4*N,1);
dGdt = zeros(N,1);
dAdt = zeros(N,1);
dOdt = zeros(N,1);
P = 16.7;
a = 0.1;
tc = 230E-6;
tp =5.4E-9;
k_c = 1/tp;
Gt = y(1:3:3*N-2);
At = y(2:3:3*N-1);
Ot = y(3:3:3*N-0);
%A is the amplitude
%G is the gain
%O is the phase
for i = 1:N
    dGdt(i) = (P - Gt(i).*((abs(At(i)))^2 +1))./tc ; 
    dAdt(i) = (Gt(i)-a).*((At(i))./tp);
    dOdt(i) = o(1,i);      %o(1,:);  
    for j = 1:N
        dAdt(i) = dAdt(i)+yita_mn(i,j)*k_c*(At(j))*cos(Ot(j)-Ot(i));
        dOdt(i) = dOdt(i)+yita_mn(i,j)*k_c*((At(j)/At(i)))*sin(Ot(j)-Ot(i));
    end
end
dy(1:3:3*N-2) = dGdt;
dy(2:3:3*N-1) = dAdt;
dy(3:3:3*N-0) = dOdt;
dy(16)= dy(6) - dy(3);
dy(17)= dy(9) - dy(6);
dy(18)= dy(12) - dy(6);
dy(19)= dy(15) - dy(12);
dy(20)= dy(3) - dy(15);
end