dolfin team mailing list archive

[Anders Logg <logg@xxxxxxxxx>]

On Fri, Oct 09, 2009 at 12:32:41PM +0200, Johan Hake wrote:
> On Friday 09 October 2009 12:23:06 Anders Logg wrote:
> > On Fri, Oct 09, 2009 at 09:31:27AM +0200, Johan Hake wrote:
> > > On Friday 09 October 2009 09:18:30 Johan Hake wrote:
> > > > On Friday 09 October 2009 09:06:19 azumi.hayakawa@xxxxxxxxxxxxxxxxxxx
> wrote:
> > > > > Hello list,
> > > > >
> > > > > I would like to use get_eigenpair function from within
> > > > > python programmes.  The 1st thing I tried is modifying
> > > > > demo/la/eigensolver/python/demo.py as follows:
> > > > >     ---- original
> > > > >     (lr, lc) = esolver.get_eigenvalue(i)
> > > > >
> > > > >     ---- modified
> > > > >     r = PETScVector(A.size(0))
> > > > >     c = PETScVector(A.size(0))
> > > > >     esolver.get_eigenpair(lr, lc, r, c, i)
> > > >
> > > > There is a bug in the Python wrapper (thanks for noticing!).
> > > >
> > > > Try using
> > > >
> > > >    lr, lc = esolver.getEigenpair(r, c, i)
> > > >
> > > > if you are on stable. If you pull the latest code you will soon be able
> > > > to use:
> > > >
> > > >    lr, lc = esolver.get_eigenpair(r, c, i)
> > >
> > > While at it shouldn't the PETScVectors also be return arguments? Leaving
> > > us with:
> > >
> > >   r, c, lr, lc = esolver.get_eigenpair(i)
> >
> > Yes, or rather
> >
> >   lr, lc, r, c = esolver.get_eigenpair(i)
> >
> > as in C++.
>
> Yes, comming soon!
>
> I added a private variable system_size that stored the size of the matrix, so
> one can check the size of the passed PETScVectors. SLEPc does not do this for
> us.
>
> > We should also add get_eigenvector to just return r and c.
>
> SLEPc does not come with this function. Isn't it natural to just have
> eigenvalues and eigenpairs, where the latter returns both values and vectors?

I think it would be natural to have eigenvalues, eigenvectors and
perhaps eigenpairs, but if it's not in SLEPc we don't need to add
eigenvectors. Nice that you fixed it.

--
Anders

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