how to develop n order matrix?

1 次查看（过去 30 天）
Jasneet Singh
Jasneet Singh 2021-3-19
评论： Jan 2021-3-22
i wish to make a matrix of nth order fromm K=[2000,-1000,0,0;-1000,2000,-1000,0;0,-1000,2000,-1000;0,0,-1000,1000; so on to nth order]
can anyone please help me with this ...
  3 个评论
显示 1更早的评论
Jasneet Singh
Jasneet Singh 2021-3-19
编辑：Jan 2021-3-19
its because last element is not hinged or fixed. so, there is only 1 force=1000 acting on it.
Walter Roberson
Walter Roberson 2021-3-19
Ran in:
K=[2000,-1000,0,0;-1000,2000,-1000,0;0,-1000,2000,-1000;0,0,-1000,1000]
K = 4×4
2000 -1000 0 0 -1000 2000 -1000 0 0 -1000 2000 -1000 0 0 -1000 1000

请先登录，再进行评论。

请先登录，再回答此问题。

回答（2 个）

Jan
Jan 2021-3-19
编辑：Jan 2021-3-19
With some guessing: You want a tridiagonal matrix with the right bottom element changed. Then:
n = 4;
K = diag(repmat(2000, 1, n)) + ...
diag(repmat(-1000, 1, n-1), 1) + ...
diag(repmat(-1000, 1, n-1), -1)
or
K = zeros(n, n);
nn = n * n;
n1 = n + 1;
K( 1:n1:nn) = 2000;
K(n1:n1:nn) = -1000;
K( 2:n1:nn-n) = -1000;
or
K = toeplitz([2000, -1000, zeros(1, n - 2)])
or
K = full(gallery('tridiag', n, -1000, 2000, -1000))
or
K = conv2(eye(n), [-1000, 2000, -1000], 'same')
any finally:
K(n, n) = 1000;
Or directly:
K = diag([repmat(2000, 1, n - 1), 1000]) + ... % Last element adjusted
diag(repmat(-1000, 1, n - 1), 1) + ...
diag(repmat(-1000, 1, n - 1), -1)
  7 个评论
显示 5更早的评论
Jasneet Singh
Jasneet Singh 2021-3-22
specifically for x w.r.t omega..
Jan
Jan 2021-3-22
This is a new question. Please post it as a new thread.

请先登录，再进行评论。

Walter Roberson
Walter Roberson 2021-3-19
Ran in:
n = 7;
MD = 2000*ones(1,n);
SD = -1000*ones(1,n-1);
K = diag(MD) + diag(SD,1) + diag(SD,-1)
K = 7×7
2000 -1000 0 0 0 0 0 -1000 2000 -1000 0 0 0 0 0 -1000 2000 -1000 0 0 0 0 0 -1000 2000 -1000 0 0 0 0 0 -1000 2000 -1000 0 0 0 0 0 -1000 2000 -1000 0 0 0 0 0 -1000 2000
Or:
n = 7;
K = zeros(n,7);
K(1:n+1:end) = 2000;
K(2:n+1:end) = -1000;
K(n+1:n+1:end) = -1000;
K
K = 7×7
2000 -1000 0 0 0 0 0 -1000 2000 -1000 0 0 0 0 0 -1000 2000 -1000 0 0 0 0 0 -1000 2000 -1000 0 0 0 0 0 -1000 2000 -1000 0 0 0 0 0 -1000 2000 -1000 0 0 0 0 0 -1000 2000

类别

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

标签

Community Treasure Hunt

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

Start Hunting!

Translated by