Thread: Finding eigenvalues for any size of matrices?

1. Finding eigenvalues for any size of matrices?

I have a problem, I need to find eigenvalues of two matrices which are k and m. I am stuck please help me . Here is my problem

1. I need to find eigenvalues for any size k and m (may be 1000-by-1000 or larger) by using matlab
2. some values of k are very big as like 1e30

2. Hi.

Originally Posted by woundedeagle
I have a problem, I am working on my thesis and I need to find eigenvalues of two matrices which are k and m. I am stuck please help me . Here is my problem

1. I need to find eigenvalues for any size k and m (may be 1000-by-1000 or larger) by using matlab
2. some values of k are very big as like 1e30
I don't get it, why not using this code: (A is your matrix)

eig(A)

matlab probably finds the eigenvalues. Otherwise: what exactly was your question?

Cheers,
Rapha

Edit:
As far as I know, matlab eig command can't calculate huge values such as 1e+30 exactly.
I don't know. Why don't you try out an example and test it?

So I need to calculate exact eigenvalues for very large matrices like 1000-by-1000. Do you know anything about it?
No, I do not.

Have you ever heard that eig command can't calculate big values?
No.

3. Originally Posted by Rapha
Hi.

I don't get it, why not using this code: (A is your matrix)

eig(A)

matlab probably finds the eigenvalues. Otherwise: what exactly was your question?

Cheers,
Rapha

As far as I know, matlab eig command can't calculate huge values such as 1e+30 exactly. So I need to calculate exact eigenvalues for very large matrices like 1000-by-1000. Do you know anything about it? Have you ever heard that eig command can't calculate big values?

4. thank you for your reply I need to focus on LAPACK routine I guess...

5. Originally Posted by woundedeagle
I have a problem, I am working on my thesis and I need to find eigenvalues of two matrices which are k and m. I am stuck please help me . Here is my problem

1. I need to find eigenvalues for any size k and m (may be 1000-by-1000 or larger) by using matlab
2. some values of k are very big as like 1e30