I am getting this error "Index exceeds the number of array elements. Index must not exceed 1."

% this is my script code to run the function

Timerange = [0,300];
ICs = 43.4;

[Tsol,Varsol] = ode15s(@Deliverable2_ODESYSFUNCTION,Timerange,ICs);

figure
plot(Tsol,Varsol(:,1))
Title('Concentration Of Hydramere In Muscles Over Time')
xlabel('Time in mins')
yaxis('Concentration')

%this is my function code 

function diffeqs=Deliverable2_ODESYSFUNCTION(t,var)

%vectors
V_s = var(1);
C_GIH = var(2);
C_L1H = var(3);
C_L2H = var(4);
C_L3H = var(5);
C_L4H = var(6);
C_CenH = var(7);
C_M = var(8);
ConcHGI = 0.3417; %Molar
%Constants
H_inAm = 43.4; %Grams
K_s = 0.045; %min^-1
Vol_GI = 2.4; %litres
Vol_L1 = 0.27; %litres
Vol_L2 = 0.27; %litres
Vol_L3 = 0.27; %litres
Vol_L4 = 0.27; %litres
Vol_CC = 11.56; %litres
Vol_Mu = 27.56; %litres
Vol_MuCC = 0.95; %litres/min
VolFr_GICC = 0.9; %litres/min
VolFr_L1GI = 0.9; %litres/min
VolFr_L1CC = 0.45; %litres/min
VolFr_L2 = 1.35; %litres/min
VolFr_L3 = 1.35; %litres/min
VolFr_L4 = 1.35; %litres/min
VolFr_CCL4 = 1.35; %litres/min
VolFr_CCMu = 0.95; %litres/min
VolFr_GI = 0.9; %litres/min
%Eqs
diffeqs(1,8) = -(K_s*V_s); %Eq1/Eq8
diffeqs(2,8) = ((VolFr_GI*(C_CenH-C_GIH)+((K_s)*(V_s)*(ConcHGI)))/Vol_GI)

end

Answer 1

[Torsten]

You define

ICs = 43.4;

Therefore, ode15s expects that you want to solve one differential equation.

Consequently, "var" in the list of inputs to your function is one single value.

function diffeqs=Deliverable2_ODESYSFUNCTION(t,var)

But you treat it as if it were an array of eight values:

%vectors
V_s = var(1);
C_GIH = var(2);
C_L1H = var(3);
C_L2H = var(4);
C_L3H = var(5);
C_L4H = var(6);
C_CenH = var(7);
C_M = var(8);