Subscript indices must either be real positive integers or logicals...help please?

yesterday this code ran just fine, but today I went back to check something and I get this error response:

Subscript indices must either be real positive integers or logicals.

Error in cylindertest (line 114)
for a=1:length(pindist+14.5)-1

The code I am trying to run is as follows:

pindistabs=(pindist+14.5)./100;
%here this is a 20 by 1 matrix, which starts at 0

Udrag=1-Upins./UNOpins;

Drag=0;

for a=1:length(pindistabs)-1

      trap=.5.*(Udrag(a)+Udrag(a+1)).*(pindistabs(a+1)-pindistabs(a));

      Drag=Drag+trap;

end

Drag=Drag*rhowake*L*UNOavgsum^2

This is an attempt to to an integration, its just odd that it was working yesterday but now I am getting an error.

Help would be appreciated. thanks.

Answer 1

[Star Strider]

Check the length of ‘pindist’ and ‘pindistabs’. My guess is that it’s a scalar, so subtracting 1 from its length results in a=0.

[Eli]

you know what I actually just closed out matlab and re opened it and its running.... good grief edit: pindist is a vector with 20 inputs. (a 1 by 20 matrix)

[Star Strider]

So problem solved?

[Eli]

haha yeah somehow.

[Star Strider]

Thanks!