Finding index of vector from its original matrix

Question

I have a matrix of 2d lets assume the values of the matrix

a =
    17    24     1     8    15
    23     5     7    14    16
     4     6    13    20    22
    1         


        

Answer 1

It depends on how you build those divided matrices. For example:

a = magic(5);
d = a([2 1 2 3],:);

then the matching rows are obviously: 2 1 2 3

---

EDIT:

Let me expand on the idea of using ismember shown by @EitanT to handle floating-point comparisons:

tf = any(cell2mat(arrayfun(@(i) all(abs(bsxfun(@minus, a, d(i,:)))<1e-9,2), ...
    1:size(d,1), 'UniformOutput',false)), 2)

not pretty but works :) This would be necessary for comparisons such as: 0.1*3 == 0.3

(basically it compares each row of d against all rows of a using an absolute difference)