MATLAB error: Subscript indices must either be real positive integers or logicals

I have the following error in MATLAB, and it's driving me nuts! I have failed to fix it for 24 hours now, and I need your help.

Error using permute
ORDER contains an invalid permutation index.

Error in trapz (line 44)
y = permute(y,perm);

Error in HIVTBsolverDEqns_original (line 63)
HIVinf3=trapz(HIVinf1,HIVinf2)

This is my code:

global Lambda mu mu_H mu_T mu_IRIS beta tau lambda_H lambda_H_1 lambda_H_2 lambda_T    lambda_T_1 lambda_T_2 gamma psi alpha

Lambda = 531062; 
mu = 3.9138943e-5;
mu_H = 1.7809071e-4;
mu_T = 3.0398002e-4;
mu_IRIS = 4.8947959e-5;
beta = 4.6575342e-4;
tau = 1.0958904e-2;
lambda_H = 1;
lambda_H_1 = 0;
lambda_H_2 = 1-lambda_H_1;
lambda_T = 1;
lambda_T_1 = 1.6666667e-2;
lambda_T_2 = (lambda_T_1)./(180.*lambda_T_1-1);
gamma = 2.7528463e-4;
psi = 0.15;
alpha = 50;

%%%== Initial conditions ==
X_SS_0 = 192941151;
X_ST_0 = 132478723;
X_HS_0 = 2422951;
X_HT_0 = 1817998;
X_S_T_T_1_0 = 161501; 
X_S_T_T_2_0 = 161501;
X_S_T_T_3_0 = 145865;
X_H_T_T_3_0 = 117;
X_H_T_T_1_0 = 7953; 
X_H_T_T_2_0 = 7953; 
X_H_T_T_T_1_0 = 3445; 
X_H_T_T_T_2_0 = 3445;
X_H_T_1_0 = 3032;
X_H_T_2_0 = 152450;
X_H_T_T_T_IRIS_0 = 82;
y0 = [X_SS_0, X_ST_0, X_HS_0, X_HT_0, X_S_T_T_1_0, X_S_T_T_2_0, X_S_T_T_3_0, X_H_T_T_3_0, X_H_T_T_1_0, X_H_T_T_2_0, X_H_T_T_T_1_0, X_H_T_T_T_2_0, X_H_T_1_0, X_H_T_2_0, X_H_T_T_T_IRIS_0];

[t,y] = ode45('HIVTBEqns',[0:1:500],y0);

X_SS = y(1);
X_ST = y(2);
X_HS = y(3); 
X_HT = y(4);
X_S_T_T_1 = y(5); 
X_S_T_T_2 = y(6);
X_S_T_T_3 = y(7);
X_H_T_T_3 = y(8);
X_H_T_T_1 = y(9); 
X_H_T_T_2 = y(10); 
X_H_T_T_T_1 = y(11); 
X_H_T_T_T_2 = y(12);
X_H_T_1 = y(13);
X_H_T_2 = y(14);
X_H_T_T_T_IRIS = y(15);

N = X_SS + X_ST + X_HS + X_HT + X_S_T_T_1 + X_S_T_T_2 + X_S_T_T_3 + X_H_T_T_3 + X_H_T_T_1 + X_H_T_T_2 + X_H_T_T_T_1 + X_H_T_T_T_2 + X_H_T_1 + X_H_T_2 + X_H_T_T_T_IRIS;

HIVinf1=0.1*[0:1:(length(X_SS)-1)];
HIVinf2=[(X_S_T_T_1+X_S_T_T_2).*(X_HS+X_HT+X_H_T_T_1+X_H_T_T_2+X_H_T_T_3)./N];
HIVinf3=trapz(HIVinf1,HIVinf2)

IRIScases1=0.1*[0:1:(length(X_H_T_T_T_1)-1)];
IRIScases2=[gamma.*(X_H_T_T_T_1+(1/178).*(179-1/lambda_T_1).*(X_H_T_T_T_2))];
IRIScases3=trapz(IRIScases1,IRIScases2)

IRISdeaths1=0.1*[0:1:(length(X_H_T_T_T_IRIS)-1)];
IRISdeaths2=[mu_IRIS.*(X_H_T_T_T_IRIS)];
IRISdeaths3=trapz(IRISdeaths1,IRISdeaths2)

AIDSdeaths1=0.1*[0:1:(length(X_H_T_T_1)-1)];
AIDSdeaths2=[mu_H.*(X_H_T_T_1+X_H_T_T_2)];
AIDSdeaths3=trapz(AIDSdeaths1,AIDSdeaths2)

I can't see what's wrong with the HIVinf3 line, or any other line for that matter! I have been using very similar code for a long time, with no problems. I don't know why this is happening.

I have tried removing the subscripts from X_SS_0 and X_ST_0 etc. but it didn't do anything. I have tried writing HIVinf3=trapz(HIVinf1,HIVinf2,1) - but it just gives me 0.

My HIVTBEqns file is working fine - let me know if you want to see it. It is not long.

Thanks for any help.

Answer 1

[Roger Stafford]

As you have defined X_SS it is a single scalar quantity: X_SS = y(1). Consequently length(X_SS)-1 is 0 and therefore HIVinf1 will consist of the single number 0. I doubt if that makes 'trapz' very happy. The same trouble seems to occur with 'IRIScases1' and 'IRISdeaths1'.

[AM]

Thank you very much sir. I didn't realize the error until you pointed me to the fact that it should say `y(:,1)`, `y(:,2)`, etc.