Index exceeds matrix dimensions.

Hello people, I have this code and on the last row I am experiencing this error.

data - 886x1 double
time - 886x1 double


WL = 60; %nastaveni delky okna
kA = 7; %vahovaci konstanty
kF = 1;
mez = 2800; %nastaveni velikost meze
Fvz = 20;
nastdelka = length(data);

figure(2);
subplot(3,1,1);
plot(time,data); %zobrazeni vybraneho kanalu eeg signalu

xlabel('Čas [s]');
ylabel('Amplituda');
title('Pitch');

for n = 1:(nastdelka*Fvz-2*WL-1)
    okno1=data(n:n+WL);
    okno2=data(n+WL+1:n+1+2*WL);
    
    Aw1(n) = sum(abs(okno1)); %vypocet amplitudy
    Aw2(n) = sum(abs(okno2)); %jednotlivych oken
    
    for m = 2:WL-1
        Fw1(n) = sum(abs(okno1(m+1)-okno1(m-1))); %vypocet frekvence
        Fw2(n) = sum(abs(okno2(m)-okno2(m-1))); %jednotlivych oken
    end 
    
    G(n) = kA*abs(Aw1(n)-Aw2(n))+kF*abs(Fw1(n)-Fw2(n)); %mira rozdilu oken <-- ERROR OCCURANCE - Index exceeds matrix dimensions.
end

[Geoff Hayes]

Boris - when I run your code (with dummy values assigned to the data and time arrays) I see the same error on this line

okno2=data(n+WL+1:n+1+2*WL);

Given that we are iterating as

for n = 1:(nastdelka*Fvz-2*WL-1)

and nastdelka is the length of data which is 886, does this make sense? Or are your arrays larger than 886x1?

[Boris Novosad]

Hello geoff, yes, nastdelka = 886. I solved the problem by running the code without the Fvz, that means I don´t have to multiply nastdelka with Fvz. But I didn't understand why did the error appeared.

Answer 1

[Image Analyst]

Put this as the first lines inside your for loop

if n+1+2*WL > length(data)
    fprintf('Skipping n = %d because %d (which is n+1+2*WL) is longer than data, which has only %d elements in it.\n'...
        n, n+1+2*WL, length(data));
    continue;
end

Now look in the command window after your loop finishes. What do you see?

[Boris Novosad]

Thanks Image Analyst, now I see why I can't run the loop properly.

Skipping n = 17689 because 17720 (which is n+1+2*WL) is longer than data, which has only 886 elements in it.