creating a diagonalmatrix with diag and add a value to it

12 visualizaciones (últimos 30 días)
Sergio Orasch el 30 de Abr. de 2020
Comentada: Ameer Hamza el 3 de Mayo de 2020
hi,
I'm trying to create a diagonal matrix, with two minor diagonals and one major diagonal. I already created the two minor, but I don't know how to create the main one.
Code:
%diagonalmatrix
D = diag((-1)*k_i,-1) + diag(k_i+k_(i+1)) + diag((-1)*k_i, 1);
diag((-1)*k_i,-1) and diag((-1)*k_i, 1) already work.
How to change diag(k_i+k_(i+1)) ?
Must I create a new matrix with the addition already included for the major diagonal? How to?
Thanks!
I included the concept in the attachment.
0 comentariosMostrar -2 comentarios más antiguosOcultar -2 comentarios más antiguos

Iniciar sesión para comentar.

Ameer Hamza el 30 de Abr. de 2020
Try this. It shows an example with symbolic variables to show that it creates the correct matrix. You can try it with k as a numeric vector
k = sym('k', [1, 8]);
A = diag(k(2:end-1),1) + diag(k(2:end-1),-1) + diag(k(1:end-1)+k(2:end));
Result
>> A
A =
[ k1 + k2, k2, 0, 0, 0, 0, 0]
[ k2, k2 + k3, k3, 0, 0, 0, 0]
[ 0, k3, k3 + k4, k4, 0, 0, 0]
[ 0, 0, k4, k4 + k5, k5, 0, 0]
[ 0, 0, 0, k5, k5 + k6, k6, 0]
[ 0, 0, 0, 0, k6, k6 + k7, k7]
[ 0, 0, 0, 0, 0, k7, k7 + k8]
2 comentariosMostrar NingunoOcultar Ninguno
Sergio Orasch el 3 de Mayo de 2020
thanks!
Ameer Hamza el 3 de Mayo de 2020
I am glad to be of help.

Iniciar sesión para comentar.

Categorías

Más información sobre Operating on Diagonal Matrices en Help Center y File Exchange.

Community Treasure Hunt

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

Start Hunting!

Translated by