Arch Linux

Proofrific

Member

Registered: 2008-01-05

Posts: 215

Missing eigs function in Octave 3.6

I upgraded from Octave 3.4.3-1 to 3.6.6-1 today. I discovered that the "eigs" function is no longer distributed with Octave (http://www.gnu.org/software/octave/NEWS-3.6.html):

The ARPACK library is no longer distributed with Octave.
If you need the eigs or svds functions you must provide an
external ARPACK through a package manager or by compiling it
yourself.

Any idea how to get this for Arch? It looks like there's an arpack package in community (http://www.archlinux.org/packages/commu … 64/arpack/), but it doesn't seem to provide Octave functions.

/dev/zero

Member

From: Melbourne, Australia

Registered: 2011-10-20

Posts: 1,247

Re: Missing eigs function in Octave 3.6

It looks like there's an arpack package in community (http://www.archlinux.org/packages/commu … 64/arpack/), but it doesn't seem to provide Octave functions.

I think that's the package you want, but I can't figure out how to get Octave to see it.

Proofrific

Member

Registered: 2008-01-05

Posts: 215

Re: Missing eigs function in Octave 3.6

Thanks for the reply. I also can't figure out how to get Octave to use ARPACK. Considering how many people use Octave in Linux, it's strange that I can't find anything on Google.

/dev/zero

Member

From: Melbourne, Australia

Registered: 2011-10-20

Posts: 1,247

Re: Missing eigs function in Octave 3.6

Thanks for the reply. I also can't figure out how to get Octave to use ARPACK. Considering how many people use Octave in Linux, it's strange that I can't find anything on Google.

Well, give it time. What I find strange is the Octave people didn't provide backwards compatability.

(Thus reinforcing the intuition I've been picking up that python is the way to go for scientific programming henceforth.)

Proofrific

Member

Registered: 2008-01-05

Posts: 215

Re: Missing eigs function in Octave 3.6

For the time being, I'm using the regular "eig" function, which returns all the eigenvalues and vectors. Then, I'm sorting it. Unfortunately, this is orders of magnitude slower than using the old "eigs" function! Sad.

/dev/zero

Member

From: Melbourne, Australia

Registered: 2011-10-20

Posts: 1,247

Re: Missing eigs function in Octave 3.6

For the time being, I'm using the regular "eig" function, which returns all the eigenvalues and vectors. Then, I'm sorting it. Unfortunately, this is orders of magnitude slower than using the old "eigs" function! Sad.

I'm not sure I understand this reference to sorting. Do you mean using the moduli of the eigenvalues? And is the eig function slow before you even get to sorting, or is the sorting itself taking a long time? Can you give an example of the matrices you're using?