Create matrix with double rows of [-1 1]

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Leonard
Leonard 2014-7-10
评论： Leonard 2014-7-11
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? :)

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采纳的回答

Ben11
Ben11 2014-7-10
编辑：Ben11 2014-7-10
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 :)
  2 个评论
Leonard
Leonard 2014-7-10
okay, thanks. That is really a good solution and quite fast! Thanks a lot again!

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更多回答（2 个）

Andrei Bobrov
Andrei Bobrov 2014-7-10
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]);
José-Luis
José-Luis 2014-7-10
编辑：José-Luis 2014-7-10
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])

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