how can i fix this error "Array indices must be positive integers or logical values"?

knowing that z2 is a function that determines the angles, vq2 are velocities determined with interpolation, d are reference angles and vel_thr are fixed speeds in the following for loop this error is thrown " Array indices must be positive integers or logical values".

x = [0 157 670 1255]; %distance

v = [0 7 30 70]; %velocity

xq = z1; %distance

vq2 = interp1(x,v,xq,'linear');

d= [-161.42 -125.58 -89.74 -53.91 -18.07 17.76 53.59 89.43 125.27 161.11];

vel_thr= [5 6 15 25 30 35 45 55 60 70];

for i=1:length(z2);

angsel=z2(i)*180/pi;

[tmp1 icol1]=min(abs(angsel-d));

[tmp2 icol2]=min(abs(360+angsel-d));

if tmp1<tmp2

icol(i)=icol1;

else

icol(i)=icol2;

end

velsel=vq2(i);

itmp=find(velsel>=vel_thr);

irow(i)=itmp(end);

prob(i)=CF20(10+irow(i),1+icol(i));

end

CF20 is a 20x11 matrix of numbers all greater than or equal to zero. i tried to insert these values both with an excel file and with a txt file, but in both cases it doesn't work.

how can I solve this problem?

Answer 1

[Cris LaPierre]

The error means that you are either using a number less that 1, or a decimal number to index a variable. As the error says, your index values must be positive integers or logicals.

With your code, I suspect icol(i) is not always an integer.

angsel=z2(i)*180/pi;

[tmp1 icol1]=min(abs(angsel-d));

Below is a simple example to explain the error

A = 1:5;
% Works
A(1)

ans = 1

% Doesn't work
A(1.5)

Array indices must be positive integers or logical values.

Answer 2

[Tewachew]

Array indices must be positive integers or logical values.

Error in load_flow8 (line 15)

Pg(round(DG(n + Num_DG),0)) = Pg(round(DG(n + Num_DG),0)) + Ps;

what is the error of this code????

[Image Analyst]

@Tewachew see the FAQ:

https://matlab.fandom.com/wiki/FAQ#%22Subscript_indices_must_either_be_real_positive_integers_or_logicals.%22

for a thorough explanation.