Error in gfconv (Galois field function) in Matlab

Question

I am trying to multiply a hexdecimal value AA by 2 in the galois field using the gfconv(a,b) function of Matlab, the console returns to me an error saying: "The input elements must be binary.", but my two elements are binary

a=hexToBinaryVector('AA');
b=de2bi(2);
c=gfconv(a,b);
disp(c);

The error code:

Error using gfconv_mex
The input elements must be binary.

Error in gfconv (line 120)
        c = gfconv_mex(varargin{:});

Error in test(line 3)
c=gfconv(a,b);

Any idea how to solve that?

Answer 1

I'm not doing all the code here, but here's the steps that I would take to solve it.

Problem

It's in binary form, but b is a vector of binary numbers.

Solution

1. Look up https://www.mathworks.com/help/matlab/ref/mat2str.html
2. Convert your vector to the string
3. Parse the string and pull out the ones and zeros
4. use str2num to convert back to a number: https://www.mathworks.com/help/matlab/ref/str2num.html

Try that and see if it works.

Note - Expansion of step 3:

if we have variable a = '[0+11]';, we can select individual characters from the string like:

 a(3)
ans = '+'
a(4)
ans = '1'
a(1)
and = '['

Therefore, you can parse the string with a loop"

for n = 1 : length(a)
    if a(n) == '1' || a(n) == '0'
        str(n) = a(n);
    end
end

Finally, convert the string:

num = str2num(str);

done