Matrix Manipulations - How to achieve these specific forms?

1 次查看（过去 30 天）
Mathias Dirksmeier
Mathias Dirksmeier 2018-9-20
评论： Mathias Dirksmeier 2018-9-20
Dear Community,
I am struggling to achieve two distinct forms of matrices.
1) I want to build a matrix with the following form and dimensions of [8760 x 2*8760]
(1 1 0 0 0 0 ...
0 0 1 1 0 0 ...
0 0 0 0 1 1 ...
...)
2) I want to build a matrix with the following form and dimensions of [2*8760 x 2*8760]
(0 0 0 0 0 0 ...
5 8 0 0 0 0 ...
0 0 0 0 0 0 ...
5 8 5 8 0 0 ...
...)
I just can't make that work, also I am fairly new to Matlab. I really hope somebody can see a solution here.
Thanks a lot, Mathias

请先登录，再回答此问题。

采纳的回答

Jos (10584)
Jos (10584) 2018-9-20
Bruno's and KSSV's answers do not create the matrices you asked for, or am I mistaken? Anyways, here are my suggestions:
N = 4 ; % small example, rather than N=8760
M1 = kron(eye(N), [1 1])
% 1 1 0 0 0 0 ...
% 0 0 1 1 0 0 ...
% 0 0 0 0 1 1 ...
% ...
M2 = kron(tril(ones(N)), [0 0 ; 5 8])
% 0 0 0 0 0 ...
% 5 8 0 0 0 ...
% 0 0 0 0 0 ...
% 5 8 5 8 0 ...
% ...
  2 个评论
Bruno Luong
Bruno Luong 2018-9-20
I'm not 100% convinced since in the example of (2) given by OP we can't see a 2x2 block far below the diagonal, so there is still a confusion whereas the lower-diagonal or 2-diagonal by block is needed.
In anycase he/she gets the receipt to build the matrix.

请先登录，再进行评论。

更多回答（2 个）

Bruno Luong
Bruno Luong 2018-9-20
>> A=diag(ones(1,5),0)+diag(ones(1,4),-1)
A =
1 0 0 0 0
1 1 0 0 0
0 1 1 0 0
0 0 1 1 0
0 0 0 1 1
>> kron(A,[2 3; 5 8])
ans =
2 3 0 0 0 0 0 0 0 0
5 8 0 0 0 0 0 0 0 0
2 3 2 3 0 0 0 0 0 0
5 8 5 8 0 0 0 0 0 0
0 0 2 3 2 3 0 0 0 0
0 0 5 8 5 8 0 0 0 0
0 0 0 0 2 3 2 3 0 0
0 0 0 0 5 8 5 8 0 0
0 0 0 0 0 0 2 3 2 3
0 0 0 0 0 0 5 8 5 8
>>
  4 个评论
显示 2更早的评论
Bruno Luong
Bruno Luong 2018-9-20
编辑：Bruno Luong 2018-9-20
The first question is easily extrapolated (I did not give the answer for the first question)
FirstQuestionMat =diag(ones(1,5),0)+diag(ones(1,4),+1)
If you claim my solution for the second quetion is good, then Jos's answer is not, and vice-versa.
Look again the results, and be clear in you mind.
Better learn the technique rather than take the answer as it is.

请先登录，再进行评论。

KSSV
KSSV 2018-9-20
Read about diag
N = 10 ;
A = diag(ones(N,1))+diag(ones(N-1,1),-1) ;

类别

在 Help Center 和 File Exchange 中查找有关 Matrix Indexing 的更多信息

标签

产品


版本

R2018a

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by