Create matrix with double rows of [-1 1]

Hey guys, I want to create a matrix which looks the following:

-1  0  0  0
 1  0  0  0
 0 -1  0  0
 0  1  0  0
 0  0 -1  0
 0  0  1  0
 0  0  0 -1
 0  0  0  1

and so on. Does anyone know a good way to do that? Maybe there is a helpful command for that :)

Thanks a lot :)

Oh, sorry, an edit:

I would also have an even more complex matrix, which would look the following...

   0  0  0  0
  -1  0  0  0
   0  1  0  0
   0 -2  0  0
   0  0  2  0
   0  0 -3  0
   0  0  0  3
   0  0  0 -4

Any suggestions? :)

Answer 1

[Ben11]

Simple answer:

clear all
clc

A = zeros(8,4)

for i =2:2:size(A,1)
    A(i-1,i/2) = (i/2)-1;
    A(i,i/2) = -i/2;

end

A

A =

       0     0     0     0
      -1     0     0     0
       0     1     0     0
       0    -2     0     0
       0     0     2     0
       0     0    -3     0
       0     0     0     3
       0     0     0    -4

There is probably a more compact way to do it though :)

[Leonard]

okay, thanks. That is really a good solution and quite fast! Thanks a lot again!

[Ben11]

My pleasure!

Answer 2

[Andrei Bobrov]

1.

out1 = kron(eye(4),[-1;1]);

2.

out2 = kron(eye(4),[1;1]);
out2(out2>0) = bsxfun(@plus,[1;-1]*(1:4),[-1;0]);

[Leonard]

This is really handy, thanks!!

Answer 3

[José-Luis]

numDiag = 4;
numVal = 2;
val1 = eye(numDiag);
val2 = val1;
val1(val1==1) = 0:3;
val2(val2 == 1) = -1:-1:-4;
your_mat = cat(3,val1,val2);
reshape(shiftdim(your_mat,2),[numDiag*numVal, numDiag])

[Ben11]

Nicely done @José-Luis!

[José-Luis]

Thanks!