How to add two rows of binary elements of matrix in matlab ?

Hello everyone, I want to add the binary matrix rows with the other. For example[1 0 1;1 1 0] i want to add these row and update in the matrix. Thanking you in advance

[Adam Danz]

It's not clear what you need help with. Could you give an example of the inputs and expected outputs?

[Stephen23]

SAGAR SALWE's "Answer" moved here:

Suppose I have matrix with elements H=[1 1 0;0 1 0] by adding the row 1 with 2 and inserting the elements in row 1 it will update to H=[1 0 0;0 1 0].

For this operation if we do addition it will just add it in double format and shows H=[1 2 0;0 1 0].

So how to add the elements considering it as binary elements in matlab.

[Guillaume]

The binary sum of 110b and 010b is 1000b, not 100b, so I don't understand your final H.

[Sagar Shriram Salwe]

https://en.wikipedia.org/wiki/Low-density_parity-check_code

See in this example H they are adding rowwise and output is just the addition of that number element by element(Actually Avoiding the carry generated).

Answer 1

[Guillaume]

Ok, you left out a lot of necessary information in your question. In particular, that your addition is performed in the 2 element galois field.

As stated on the wiki page, addition in GF(2) is simply a logical xor, so:

H(1, :) = xor(H(1, :), H(2, :))

Or you could use the features of the Communication System Toolbox (which I don't have) which fully support galois fields computation and has functions for error detection. It may even have your LDPC algorithm already implemented.

[Sagar Shriram Salwe]

Hello sir, Thanks a lot it worked. Thanks for the suggestion i will go through it.

[Sagar Shriram Salwe]

As in https://en.wikipedia.org/wiki/Low-density_parity-check_code the G*transpose(H)=0 mentioned but this operation is yielding non binary values how to resolve this issue.

[Guillaume]

I'm afraid this is way outside my area of expertise. I learned this stuff 20 years ago and haven't used it since then.

[Sagar Shriram Salwe]

Actually while doing manually and adding the same quantities we are getting Null matrix. By multiplying G and Transpose of H and adding the elements by xor resolve this issue. In matlab for to do same any function is available or not?

Answer 2

[Adam Danz]

Use bi2de() to convert the binary vectors to decimal; then add; then convert back to binary vector using de2bi(). These function are from communications toolbox.

H=[1 1 0;0 1 0]
bisum = de2bi(sum(bi2de(H)))

If you'd like to replace the first row of H with the new sum vector,

H(1,:) = de2bi(sum(bi2de(H)))

[Sagar Shriram Salwe]

Its not adding the element by element and ignoring the carry generated. Please go through the link i want to do this operation mentioned in step 2 https://en.wikipedia.org/wiki/Low-density_parity-check_code

[Adam Danz]

Yeah, this answer addresses adding binary matrix rows which was your original question prior to Guillaume looking into what you really wanted to do.

[Sagar Shriram Salwe]

Thank you!!! I Actually formulated as per the wiki page. It should be GF(2) addition i.e. xor operation.