For loop problem.

I am trying to loop my calculations with a long data, but I do something wrong.

 size(a)=15 186
 for i=1:size(a,1)
   bcn(i,:)=abs(a(i,:)-a(i+1,:));
 end

The idea is that bcn should equal like that bcn=abs(a(1,1)-a(2,1))+abs(a(1,2)-a(2,2))+abs(a(1,3)-a(2,3))+abs(a(1,4)-a(2,4))+...+abs(a(i,:)-a(i+1),:);

As you can see this is quite extensive procedure. I know that my first column only have 15 entries. But is there any trick to acquire those numbers anyway. Clearly I am interested in the differences between the data.

Cheers! Will appreciate any help!

[Darkhan Kenestegi]

I actually get the answer anyway. So I kinda already solved. But now I need to know how I can improve the code so I can make difference with any row, not just consequential...

Answer 1

[Stephen23]

 abs(diff(a,1))

and then play around with sum. For example:

>> A = randi(9,5,10)
A =
   8   1   7   6   2   3   1   9   1   8
   7   4   9   3   6   2   2   5   2   1
   5   8   3   5   6   9   9   8   9   9
   9   4   9   6   2   3   9   3   5   4
   4   2   1   2   2   6   3   3   5   8
>> B = abs(diff(A,1))
B =
   1   3   2   3   4   1   1   4   1   7
   2   4   6   2   0   7   7   3   7   8
   4   4   6   1   4   6   0   5   4   5
   5   2   8   4   0   3   6   0   0   4
>> sum(B,1)
ans =
   12   13   22   10    8   17   14   12   12   24
>> sum(B,2)
ans =
 27
 46
 39
 32

[Darkhan Kenestegi]

Thanks! you managed to put my code into one line xD

Do you know how can I find difference from different rows? For example row 1 and 3, row 1 and 4, row 3 and 6 etc...

[Darkhan Kenestegi]

Changing numbers in diff(A,1) not really does what I wanted. So diff(A,2) takes the difference of the difference, which is not really an aim, although it is interesting.

diff(A,1) calculates difference only between adjacent rows.

[Stephen23]

 abs(a(1,1)-a(2,1))+abs(a(1,2)-a(2,2))+abs(a(1,3)-a(2,3))+abs(a(1,4)-a(2,4))+...

could be written like this:

 sum(abs(diff(A,1)),2)