Array indices must be positive integers or logical values.

E = 10;
R1 = 10e3;
R2 = 1e3; 
R3 = 4.7e3; 
R4 = 10e3;
R5 = 10e3; 
RX = 1e3;
RY = 1e3;

J = [E/R5 ; - E/R5; 0 ];

RYs = logspace(-3, 10, 10000);

IXs = [];

for ry = RYs
    
    G = [ -(1/R5+1/R4+1/RX) 1/R5 1/RX;
        1/R5 -(1/R5+1/R2+1/ry+1/R1) 1/R1;
        1/RX 1/R1 -(1/R1 + 1/R3 + 1/RX) ];
    
        V = G\J;
        
        IXs(end+1) = ( V(3) - V(1) ) / RX;
end;

PXs = IXs .* IXs * RX; 

figure('Name','RYandIXs','NumberTitle','off'); semilogx(RYs, IXs);

figure('Name','RYandPXs','NumberTitle','off'); semilogx(RYs, PXs);

maxIXs= max(IXs),
minIXs =min(IXs), 
maxPXs= max(PXs), 
minPXs = min(PXs)

MaxPXsAt = RYs(find(PXs == max(PXs)))

So this is the code I have written. Everything works fine except for the two min- functions. When I run the code I get the message "Array indices must be positive integers or logical values.". I have searched the internet for answers but no solution seems to be the one for me. Anyone know what might be the problem? Thank you :)

Answer 1

[meghannmarie]

I ran your code and it works for me. This leads me to believe you might have a variable in your workspace named min. Try this:

which min

If that tells you min is a variable, rename that variable to something else.

[Tove Rudöfors]

Thank you so much! it was a variable and by changing it everything works. You are the best :)

[meghannmarie]

I have had this happed to me numerous times by naming variables min, mean, max. So I figured thats what was happening when you posted this. Now I name my variables mn, avg, and mx.

[Tove Rudöfors]

That's a really good tip! I will definitely be doing that too from now on. Thank you