Code to generate matrix
1 回表示 (過去 30 日間)
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bold Hello,
I have this matrix, can someone please adv how to write the code:
A = [ 4 -1 0 0 0 0 0 0 0 -1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0;
-1 4 -1 0 0 0 0 0 0 0 -1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0;
0 -1 4 -1 0 0 0 0 0 0 0 -1 0 0 0 0 0 0 0 0 0 0 0 0 0 0;
0 0 -1 4 -1 0 0 0 0 0 0 0 -1 0 0 0 0 0 0 0 0 0 0 0 0 0;
0 0 0 -1 4 -1 0 0 0 0 0 0 0 -1 0 0 0 0 0 0 0 0 0 0 0 0;
0 0 0 0 -1 4 -1 0 0 0 0 0 0 0 -1 0 0 0 0 0 0 0 0 0 0 0;
0 0 0 0 0 -1 4 -1 0 0 0 0 0 0 0 -1 0 0 0 0 0 0 0 0 0 0;
0 0 0 0 0 0 -1 4 -1 0 0 0 0 0 0 0 -1 0 0 0 0 0 0 0 0 0;
0 0 0 0 0 0 0 -1 5 0 0 0 0 0 0 0 0 -1 0 0 0 0 0 0 0 0;
-1 0 0 0 0 0 0 0 0 4 -1 0 0 0 0 0 0 0 -1 0 0 0 0 0 0 0;
0 -1 0 0 0 0 0 0 0 -1 4 -1 0 0 0 0 0 0 0 -1 0 0 0 0 0 0;
0 0 -1 0 0 0 0 0 0 0 -1 4 -1 0 0 0 0 0 0 0 -1 0 0 0 0 0;
0 0 0 -1 0 0 0 0 0 0 0 -1 4 -1 0 0 0 0 0 0 0 -1 0 0 0 0;
0 0 0 0 -1 0 0 0 0 0 0 0 -1 4 -1 0 0 0 0 0 0 0 -1 0 0 0;
0 0 0 0 0 -1 0 0 0 0 0 0 0 -1 4 -1 0 0 0 0 0 0 0 -1 0 0;
0 0 0 0 0 0 -1 0 0 0 0 0 0 0 -1 4 -1 0 0 0 0 0 0 0 -1 0;
0 0 0 0 0 0 0 -1 0 0 0 0 0 0 0 -1 4 -1 0 0 0 0 0 0 0 -1 ;
0 0 0 0 0 0 0 0 -1 0 0 0 0 0 0 0 -1 5 0 0 0 0 0 0 0 0;
0 0 0 0 0 0 0 0 0 -1 0 0 0 0 0 0 0 0 3 -1 0 0 0 0 0 0;
0 0 0 0 0 0 0 0 0 0 -1 0 0 0 0 0 0 0 -1 3 -1 0 0 0 0 0;
0 0 0 0 0 0 0 0 0 0 0 -1 0 0 0 0 0 0 0 -1 3 -1 0 0 0 0;
0 0 0 0 0 0 0 0 0 0 0 0 -1 0 0 0 0 0 0 0 -1 3 -1 0 0 0;
0 0 0 0 0 0 0 0 0 0 0 0 0 -1 0 0 0 0 0 0 0 -1 3 -1 0 0;
0 0 0 0 0 0 0 0 0 0 0 0 0 0 -1 0 0 0 0 0 0 0 -1 3 -1 0;
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 -1 0 0 0 0 0 0 0 -1 3 -1 ;
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 -1 0 0 0 0 0 0 0 -1 3 ];
b=[0;0;0;0;0;0;0;0;0;0;0;0;0;0;0;0;0;5;0;0;0;0;0;0;0;5];
3 件のコメント
Guillaume
2016 年 5 月 12 日
編集済み: Guillaume
2016 年 5 月 12 日
Well, then you have to explain the logic behind the matrix generation.
As far as I can tell b is just a zero column with 5 in two (random?) locations and A is a matrix that could be generated with toeplitz except that some (random?) -1 get replaced by 0 and the main diagonal is either 3, 4 or 5 (depending on ?)
採用された回答
Walter Roberson
2016 年 5 月 12 日
You can put it together using diag()
d0 = [repmat(4,1,8), 5, repmat(4,1,8), 5, repmat(3,1,8)];
d1 = ones(1, length(d0)-1);
d9 = ones(1, length(d0)-9);
A = diag(d0,0) + diag(d1, -1) + diag(d1, 1) + diag(d9, -9) + diag(d9, 9);
b = [zeros(1,17), 5, zeros(1, 7), 5];
5 件のコメント
Walter Roberson
2016 年 5 月 12 日
d0 = [repmat(4,1,8), 5, repmat(4,1,8), 5, repmat(3,1,8)];
d9 = -ones(1, length(d0)-9);
d1 = [-ones(1,8), 0, -ones(1,8), 0, -ones(1,7)];
A = diag(d0,0) + diag(d1, -1) + diag(d1, 1) + diag(d9, -9) + diag(d9, 9);
For your purpose it might make sense to construct
d1 = one(1,length(d0)-1);
d1(9:9:end) = 0;
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