Create matrix with double rows of [-1 1]

Question

Leonard 2014-7-10

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https://ww2.mathworks.cn/matlabcentral/answers/141290-create-matrix-with-double-rows-of-1-1

评论： Leonard 2014-7-11

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

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

Any suggestions? :)

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Answer 1

Ben11 2014-7-10

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https://ww2.mathworks.cn/matlabcentral/answers/141290-create-matrix-with-double-rows-of-1-1#answer_144516

编辑：Ben11 2014-7-10

在 MATLAB Online 中打开

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 :)

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Leonard 2014-7-10

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

Ben11 2014-7-10

My pleasure!

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Answer 2

Andrei Bobrov 2014-7-10

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此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/141290-create-matrix-with-double-rows-of-1-1#answer_144530

在 MATLAB Online 中打开

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]);

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Leonard 2014-7-11

This is really handy, thanks!!

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Answer 3

José-Luis 2014-7-10

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此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/141290-create-matrix-with-double-rows-of-1-1#answer_144519

编辑：José-Luis 2014-7-10

在 MATLAB Online 中打开

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])