Related to comparing two vectors

Hello all, In my work I came across a situation where I have two vectors of dimension 8 X 1 each.

These vectors have all zero values except at any two rows.

My query is how to compare the non-zero positions of these two matrices in MATLAB.

Any help in this regard will be highly appreciated.

[NAVNEET NAYAN]

From your query, it appears that you want to find the location of non-zero values from both vectors and then compare it (correct me if I am wrong). Can you please explain what kind of comparison do you want?

[Dyuman Joshi]

@chaaru datta, Is this question the same as - https://in.mathworks.com/matlabcentral/answers/2037316-extract-indices-of-vector?s_tid=srchtitle ?

Answer 1

[Fabio Freschi]

You can compare the two complete vectors (you also compare zeros, but who cares?)

% data
v1 = [0 0 0 4 5 0 0 0].';
v2 = [0 0 0 4 6 0 0 0].';
v3 = [0 0 0 4 5 0 0 0].';

% engine
v1eqv2 = isequal(v1,v2)

v1eqv2 = logical
   0

v1eqv3 = isequal(v1,v3)

v1eqv3 = logical
   1

or you can compare nonzero indices and values

% data
v1 = [0 0 0 4 5 0 0 0].';
v2 = [0 0 0 4 6 0 0 0].';
v3 = [0 0 0 4 5 0 0 0].';

% find nonzeros
[idx1,val1] = find(v1);
[idx2,val2] = find(v2);
[idx3,val3] = find(v2);

% engine
v1eqv2 = isequal(idx1,idx2) && isequal(val1,val2)

v1eqv2 = logical
   1

v1eqv3 = isequal(idx1,idx3) && isequal(val1,val3)

v1eqv3 = logical
   1

If you only want to check if the nonzero positions are the same

% data
v1 = [0 0 0 4 5 0 0 0].';
v2 = [0 0 0 4 6 0 0 0].';

% find nonzeros
idx1 = find(v1);
idx2 = find(v2);

% engine
v1eqv2pos = isequal(idx1,idx2)

v1eqv2pos = logical
   1