Change the sign of a particular element in a matrix

Hi, I have a problem in the following matrix: A=[ -1 1 0 0 0 0; 0 -1 1 0 0 0 ; 0 0 -1 1 0 0; 0 0 0 0 -1 1 ; 0 0 0 0 0 -1 ; 0 0 0 0 0 0];

In the above matrix, I need to change only the element -1 by +1, while others remaining the same. For, small matrix, it is possible by defining the row and column elements but for large matrix, is there any way of doing it programatically in matlab as the dimension of the matrix may be larger than this. Please help me in this regard.

Thanking You!

Answer 1

[Muruganandham Subramanian]

find(A==-1)=1

[EDITED, Jan, copied from comments] Better: A(A==-1)=1;

or

A=abs(A)

[Azzi Abdelmalek]

find(A==-1)=1 will not change A. That will create a variable find

[Muruganandham Subramanian]

Sorry..Azzi Its

A(A==-1)=1;

[Pranjal Pathak]

Thanks for the answer,it worked out!

Answer 2

[Image Analyst]

What do you mean change it by +1? Do you mean change it TO +1, or change it by +1 by adding +1 to the -1 so that you get 0? Here's three different ways to do the two possible meanings of your question:

A = [ -1 1 0 0 0 0; 0 -1 1 0 0 0 ; 0 0 -1 1 0 0; 0 0 0 0 -1 1 ; 0 0 0 0 0 -1 ; 0 0 0 0 0 0]
A(A == -1) = 1

A = [ -1 1 0 0 0 0; 0 -1 1 0 0 0 ; 0 0 -1 1 0 0; 0 0 0 0 -1 1 ; 0 0 0 0 0 -1 ; 0 0 0 0 0 0]
A(A == -1) = 0

A = [ -1 1 0 0 0 0; 0 -1 1 0 0 0 ; 0 0 -1 1 0 0; 0 0 0 0 -1 1 ; 0 0 0 0 0 -1 ; 0 0 0 0 0 0]
elementsToChange = A == -1;
A(elementsToChange) = A(elementsToChange) + 1

[Shaun VanWeelden]

Image Analyst, your always so thorough in your answers, I love it

[Jan]

@Shaun: You can vote this answer, if you find it useful.