For Error: ??? Index exceeds matrix dimensions.

Dear Sir,

This part of my code...I don't know why I have this error "??? Index exceeds matrix dimensions"...

T =[];

for j = 41:41:492

        S1Secondcell1 = x1Firstrow16 (j+1: j+j, :);
        X1= S1Secondcell1 (:,1);
        Y1 = S1Secondcell1(:,2);
        p1 = polyfit(X1,Y1,20)

        T = [T; p1];
 end

Answer 1

[per isakson]

You don't supply enough information to make it possible for us to find the cause of the error.

Here are some links on debugging in Matlab

• Debugging in MATLAB
• Debugging session
• Debugging Approaches

Hint: what does

    size( x1Firstrow16 )

return?

Answer 2

[Azzi Abdelmalek]

Check the sizes of your arrays

[Mohamed Elwakdy]

Dear Azzi,

I think that the arrays have the same size... Could you please explain me where is the error in more details??

thank you very much

[Azzi Abdelmalek]

Without your data, I can't find where is the error

[Mohamed Elwakdy]

Dear Azzi,

Thank you very much on your interest...

For the data file, please visit the website below:

https://docs.google.com/file/d/0B254WGMh1VZTLUMyOHRPdEdMUE4xc3JNX1Z2Qkg5QTZuSE04/edit

This is my full code:

load TCheckingclass6.txt;

Firstrow16 = TCheckingclass6(1,:);

x1Firstrow16 = vec2mat(Firstrow16,2); R = size(x1Firstrow16); % 538 rows and 2 columns

S1Secondcell41= x1Firstrow16(1:41,:); X1 = S1Secondcell41 (:,1); Y1 = S1Secondcell41 (:,2); p1 = polyfit(X1,Y1,20);

T =[];

 for j = 41:41:492

        S1Secondcell1 = x1Firstrow16 (j+1: j+j, :);
        X2= S1Secondcell1 (:,1);
        Y2 = S1Secondcell1(:,2);
        p2 = polyfit(X2,Y2,20);

        T = [T; p2];
 end

Thank you very much

Answer 3

[Roger Stafford]

I rather think your trouble is caused by the way you indexed the array 'x1Firstrow16'. Its rows are successively indexed as:

   41:82
   83:164
  123:246
  165:328
  .......
  493:984

These are overlapping each other more and more as j increases. Somehow I doubt if that is what you meant to do, and I doubt that the array has 984 rows. You can check that easily with the 'size' command.

[Mohamed Elwakdy]

Dear Roger,

From these steps: for j = 41:41:492 S1Secondcell1 = x1Firstrow16 ( j+1: j+j , :); I am looking to have this output:

42:82

83:123

124:164 .......

If the codes above is wrong ... How can I fixed it??

Thank you very much