Index expression out of bounds. Attempted to access element 2. The valid range is 1-1.“2”

I keep getting this error, my desired output is to get abs(I(2,ii(a))-I(2,ii(a)-1) so that when ii(a)=2, I want I(2,2) minus I(2,1) which is 5.1 minus 5.0 : Index expression out of bounds. Attempted to access element 2. The valid range is 1-1."2".

The error is due to this line:

arr(1,ii(a)) = arr(1,ii(a)) + abs(I(2,ii(a))-I(2,ii(a)-1));.

I define I as the following in .mat file:

save data -v7.3 'I' load('data.mat','I'); 

I =

Columns 1 through 6

     0    1.0000    2.0000    3.0000    4.0000    5.0000
5.0000    5.1000    5.2000    5.2000    5.5000    5.9000

    Column 7

    6.0000
    6.0000

[want2know]

What's wrong with accessing row 2 of variable I?

Answer 1

[Azzi Abdelmalek]

Check the sizes of ii and I, check also if all values in ii are positive integer

[want2know]

All ii vlues are positive. The size of ii is 1x5, the size of I is 2x5. I is a timeseries object in .mat file, the first row is time and the second row is data. I want to access the data in row 2 instead of the time in row 1. Am I doing something wrong?

[want2know]

i read this link http://www.mathworks.co.uk/matlabcentral/answers/9866 answered by Arnaud Miege , is it not possible to access the data in row 2 by coding I(2,xx)??

[Azzi Abdelmalek]

I asked if all values in ii are positive and integer

[want2know]

Yes all ii vlues are positive and integer, Sir

[Azzi Abdelmalek]

Post your code and the values of ii

[want2know]

function arr= fcn(I,count,oldval)
persistent integ_signal
if isempty( integ_signal)
  integ_signal=zeros(1,5)
end
persistent a
if isempty(a)
  a=zeros(1)
end
%integ_signal=zeros(5,1);
arr=zeros(1,5);
ii=zeros(1,5);
aa=zeros(2,5);
integ_signal=oldval;
coder.extrinsic('load');
aa=load('data.mat','I');
%for ii = 1:length(count)
%if count(ii) == 1
if count==1
  a=1;
  ii(a)=count;
  integ_signal(1,ii(a)) = 10; % Initial Condition
end
if count ~= 1
  a=count;
  ii(a)=count;
  integ_signal(1,ii(a))=  integ_signal(1, ii(a)-1); % Or, (count(ii-1),1)
  arr(1,ii(a)) = integ_signal(1,ii(a));
  arr(1,ii(a)) = arr(1,ii(a)) + abs(aa(2,ii(a))-aa(2,ii(a)-1));
end
a = a + 1;
end

[Azzi Abdelmalek]

there are some problems in your code

function arr= fcn(I,count,oldval) % I is not used in your code

aa=zeros(2,5); this line is unnecessary, because just after you wrote also aa=load('data.mat','I'); in this case the result is a structure array named aa with field I , note that I has nothing to do with I in function argument. to get the value

aa=aa.I

[want2know]

Got it, i changed according to your suggestion and it worked, however the system is giving wrong output mathematically. Do you mind to have a look on this new post? I created new question http://www.mathworks.com/matlabcentral/answers/105388-calculation-error-system-always-gives-output-0-0-0-value-in-index-3-value-in-index-1-0