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can anyone help me with getting my head around eigenvector centrality?

What is the formula I need to use to work it out and then how do i use this formula to work it out?

Thank You
Original post by mickymouse1995
can anyone help me with getting my head around eigenvector centrality?

What is the formula I need to use to work it out and then how do i use this formula to work it out?

Thank You


Before I give you the formula, do you know what an eigenvector is? This will then make the formula make sense :smile:P
Original post by Slowbro93
Before I give you the formula, do you know what an eigenvector is? This will then make the formula make sense :smile:P



yeah i know what an eigenvector is :smile:
Original post by mickymouse1995
yeah i know what an eigenvector is :smile:


Okay :smile:

In that case, suppose I have some vector v\mathbf{v} Then my vector is an eigenvector if for some square matrix A:

Av=αvA\mathbf{v}=\alpha \mathbf{v} where α\alpha is some real or complex number.

Now if you look at my equation you can see that I can rearrange it such that:

(AαI)v=0(A-\alpha \mathbf{I})\mathbf{v} =0

Do you know what you can do to find the corresponding values of alpha? :smile:
yeah im just confused how i go from a network to a matrix...
Original post by mickymouse1995
yeah im just confused how i go from a network to a matrix...


I would recommend this link. This may be able to clear some stuff for you :smile: https://www.khanacademy.org/math/linear-algebra/alternate_bases/eigen_everything/v/linear-algebra-introduction-to-eigenvalues-and-eigenvectors
sooooo confused....

I have been asked to define eigenvector centrality in as much detail as necessary to calculate it in practical examples...

i have no idea what this means.....
Original post by mickymouse1995
sooooo confused....

I have been asked to define eigenvector centrality in as much detail as necessary to calculate it in practical examples...

i have no idea what this means.....


Found this page: http://en.wikipedia.org/wiki/Centrality

Didn't do any networks in my undergrad so can't help with the application. Sorry :frown:
Original post by mickymouse1995
sooooo confused....

I have been asked to define eigenvector centrality in as much detail as necessary to calculate it in practical examples...

i have no idea what this means.....


Not something I've studied, but in case it's of any use:

There is an algorithm for eigenvector centrality (google), which is basically choose a starting vector, e.g. (1,1,...,1), apply adjacency matrix, scale the result, repeat until there is no change.
Original post by ghostwalker
Not something I've studied, but in case it's of any use:

There is an algorithm for eigenvector centrality (google), which is basically choose a starting vector, e.g. (1,1,...,1), apply adjacency matrix, scale the result, repeat until there is no change.



where did you find this info???
thank you Xx
Original post by mickymouse1995
where did you find this info???


www.cl.cam.ac.uk/teaching/1213/L109/stna-lecture3.pdf

Pages 22 - 24.

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