norm() - Subscript indices must either be real positive integers or logicals.

Hello everyone, I'm having trouble with my script. First off, this is the relevant code:

rawData = importdata('part1.csv', ';', 1);
data = rawData.data;
zeilen = size(data,1);

for i = 1:zeilen
LHuef=[data(i,3);data(i,4);data(i,5)];
RHuef=[data(i,6);data(i,7);data(i,8)];
MHuef=[data(i,9);data(i,10);data(i,11)];
LKnie=[data(i,12);data(i,13);data(i,14)];
RKnie=[data(i,18);data(i,19);data(i,20)];
ORueck=[data(i,30);data(i,31);data(i,32)];

LHuef1=[LHuef(2);LHuef(3)];
LKnie1=[LKnie(2);LKnie(3)];
ORueck1=[ORueck(2);ORueck(3)];
MHuef1=[MHuef(2);MHuef(3)];
RHuef1=[RHuef(2);RHuef(3)];
RKnie1=[RKnie(2);RKnie(3)];

HKL = (LHuef1 - LKnie1);
HR = (ORueck1 - MHuef1); 
HKR = (RHuef1 - RKnie1);

dalphaL = acosd(abs(dot(HKL,HR))/(norm(HKL)*norm(HR)));

I'm getting this error:

    Subscript indices must either be real positive integers or logicals.
    Error in ExcelVariante (line 62)
    dalphaL = acosd(abs(dot(HKL,HR))/(norm(HKL)*norm(HR)));

I tested a bit and found that "norm" doesn't seem to be working correctly here. The data is just x-y-z-coordinates, I set these vectors and calculate a lot of stuff with it. Including said angle-calculation which gives me back an error. If I set my vectors HKL, HR and HKR to fixed values it works. I have no clue why it does not work with my data matrix though.

If necessary I can provide more code, but I could not find anymore code relevant for the line causing my error.

Thanks in advance everyone.

Answer 1

[Thorsten]

Make sure that you have not used any of these as a variable

which norm
which abs
which acosd
which dot

[Jonas]

Oh my god thank you so much. Now I feel dumb though. I did have a variable called 'norm' that I didn't even use yet.

Answer 2

[Guillaume]

Let's work backward from the error: "Subscript indices must either be real positive integers or logicals". What it's telling you is: you're trying to index a matrix, and the index is not integer or not positive. So why would matlab think you're trying to index a matrix in the line

dalphaL = acosd(abs(dot(HKL,HR))/(norm(HKL)*norm(HR)));

when it's not your intention? The only way it can think that is if it thinks that norm or dot or abs or acosd is a matrix. For matlab to think that, it must mean that one of them exists as a variable.

So find out where you've created a variable called norm, (or dot or abs or acosd) and rename it to something that does not shadow one of matlab's built-in functions.

[Jonas]

Thank you as well. Would've helped me just as much.