Regarding Matrix row subtraction! Please Help, Urgent

HI

Consider this example

A=[6 5 6;2 4 1] A(2,2)-A(1,2) gives me a zero value. However I needed the real value in positive. I do understand that abs() would help in making it positive however I get a zero value to start with. CAN SOMEONE PLEASE HELP

[Rik]

You should avoid the word urgent. The overwhelming majority of answers and other support provided on this forum is from volunteers. You can improve your chances on a fast answer by following the advice here. If someone reads your question and finds it interesting enough, you will get an answer or at least some pointers to help you along. Using words like urgent or all caps please help don't improve the odds. Actually, some people actively avoid questions with these kind of words.

Answer 1

[John D'Errico]

Works for me.

A=[6 5 6;2 4 1];
A(2,2)-A(1,2) 

ans =
    -1

I would suggest that A is probably of class uint8. (Or a similar integer class.) Verify that by whos.

whos A
  Name      Size            Bytes  Class     Attributes
  A         2x3                48  double

You can see that A is a double. See what happens if we change the class of A. It still looks very much the same, but...

A = uint8(A)
A =
  2×3 uint8 matrix
   6   5   6
   2   4   1

A(2,2)-A(1,2)
ans =
  uint8
   0

Now we get zero.