Difference between rank(S) and rank(gf(S)) when S is a matrix

Hi All,

Can someone please tell me the difference between the normal rank of a binary matrix and GF2 rank of a binary matrix. See in below example,

>> S = [1 0 1 1; 1 0 0 1; 0 1 0 1; 1 1 0 0]

S =

     1     0     1     1
     1     0     0     1
     0     1     0     1
     1     1     0     0

>> rank(S)

ans =

     4

>> rank(gf(S))

ans =

     3

Why is rank(gf(S)) different to rank(S)?

Thanks in advance for your support.

Answer 1

[LUCA Malinverno]

The difference is this one: When you use the gf command you are processing a binary matrix.

In your case you should use the RANK(GF(S)) command if your matrix is a binary one. If is a matrix in base 10, you have to use simply the RANK command.

here ther's a discussion may help you: http://www.mathworks.it/matlabcentral/newsreader/view_thread/37571