Subscript indices must either be real positive integers or logicals.

I have this code:

%Deposition by diffusion - still air

d_k = [1.81, 1.414, 1.115, 0.885, 0.706, 0.565, ...
    0.454, 0.364, 0.286, 0.218, 0.162, 0.121, ...
    0.092, 0.073, 0.061, 0.049, 0.048, 0.039, ...
    0.037, 0.035, 0.033, 0.030, 0.028, 0.024]*10^-2; %Airways diameter
R_k=d_k/2;
l_k=[12.456, 3.614, 2.862, 2.281, 1.78, 1.126 ...
    0.897, 0.828, 0.745, 0.653, 0.555, 0.454,...
    0.357, 0.277, 0.219, 0.134, 0.109, 0.091,...
    0.081, 0.068, 0.068, 0.068, 0.065, 0.073]; %airways lenght



n=0; %besselzero inputs: n,k,kind
k=5; 
kind=1;
am0=besselzero(n,k,kind); % bessel roots
Co=1;
k_bol=1.38*10^(-23); %J/K
T=310; % Kelvin
dp=0.01; %μm
Cc=23.06; % for d=0.01μm 
visc=1.8*10^(-5); %kg/ms
D=k_bol*T*Cc*10^6/(3*pi*visc*dp) %m^2/s

%---------------------------------------------%
   syms tp
dcdr_R=sym(zeros(1,24));
deposition=sym(zeros(1,24));
dep=zeros(9,24);
for N=1:24
    syms tp
    assume(tp,'real')
    
    for k=1:5
    dcdr_R(N)=@(tp) dcdr_R(N)+2*Co/(am0(k)*besselj(1,am0(k)))*exp(-(am0(k))^2*D*tp/(R_k(N))^2)*(-am0(k)/R_k(N))*besselj(1,am0(k));
    end
    
    deposition(N)=@(tp) (2*pi*R_k(N)*l_k(N))*(-D*dcdr_R(N));
    
    for t=1:5
       dep(t,N)= dep(t,N)+subs(deposition(N),tp,t);
    end
    

end

I want to run it for t=1:.5:5, but when I do that i take the following error:

Subscript indices must either be real positive integers or logicals.

Should I define the array dep as something else? Please help me, I am new in matlab!!!!

Thanks in advance!

[Stephen23]

"I want to run it for t=1:.5:5"

What is the 1.5th row of dep?

You seem to be confusing indices with data.

[Eleni Parasxaki]

Yes I get what you mean...I really messed it up. You actually mean that there is not the 1.5 cell in the arrray, right? But what can I do with the time loop? I am trying to take results for small times, for example from 1 to 5 seconds I want to take results let's say for time 1.0001 ,1.0002 etc.

Answer 1

[Stephen23]

It is much simpler to iterate over indices, than iterating over data values. So rather than this:

for t = 1:5 % iterate over data (avoid this)
   ...
end

you should be doing something like this:

TV = 1:0.001:5; % data vector
for k = 1:numel(TV) % iterate over indices (simpler)
    t = TV(k);
    ...
end

Note that

1.0001,1.0002,... data
   1st,   2nd,... indices

[Stephen23]

Eleni Parasxaki's "Answer" moved here:

Okay it worked! Thank you very much for your time and your help!:)

[Stephen23]

@Eleni Parasxaki: Remember to accept my answer if it helped!