[SciPy-dev] Comments on API for Matlab's eigs equivalent (computing a few eigenvalues only)

Tiziano Zito opossumnano@gmail....
Sun Feb 7 02:14:29 CST 2010


> > How does the new implementation relate to the existing implementation
> > of selecting just a few eigenvalues in a range that is possible with
> > the current scipy.linalg.eigh ?
> 
> Mostly a different interface (the underlying lapack function is the
> same). What bothers me with the current API for eigen/svd
> decompositions is the lack of consistency. The current eigh also does
> not enable to look for eigenvalues in a value range (e.g. all eigen
> values between 2 and 3), and I intend to add support for non-symmetric
> eigenvalues as well.

Is the new eigs function going to supersede eigh? I did not know
that LAPACK allowed selecting a range of eigenvalues by value. Which
are the LAPACK routines you are referring to?
I agree that a consistent interface for eigen/svd decomposition is
good, I am on the other hand a little unsure that linalg needs an
eigs function together with an eigh function. Why not simply change the
eigh interface in a backward compatible way?

ciao,
tiziano



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