From: KIRK, BENJAMIN (JSCEG) (NASA) <benjamin.kirk1@na...>  20051214 19:03:16
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You might want to check out SLEPc, an interface on top op PETSc specifically for Eigenvalue problems. Stefan added an interface to it from libMesh some time ago, and he might have some comments on this thread too. Ben _____ From: libmeshusersadmin@... [mailto:libmeshusersadmin@...] On Behalf Of Michael Povolotskyi Sent: Wednesday, December 14, 2005 12:22 PM To: Roy Stogner; libmesh  ML Subject: Re: [Libmeshusers] Eigenvalue problem 1) Yes, I mean Hx = gSx, sorry for the error. 2) Does it mean that if one wants to use Libmesh just for one complex problem, then all the other problems also have to be complex? thank you, Michael. Roy Stogner wrote: On Wed, 14 Dec 2005, Michael Povolotskyi wrote: I have to solve an eigenvalue problem for a quantum physics calculations. My questions are: 1) Is it possible to solve a general eigenvalue problem like Hx = Sx, where H and S are known matrixes. Are you sure you don't mean Hx = gSx, where H and S are known but g is unknown? That's the generalized eigenvalue problem built into SLEPc, which is currently the only eigenvalue solve libMesh interfaces with. Our SLEPc support currently only handles the simple Hx = gx problem, and a new interface would have to be written to get generalized eigenvalues. 2) Is it possible to have complex (selfconjugated) matrixes? If both PETSc and libMesh have been compiled with complex number support on, then the default PetscScalar and libMesh Number types will both be std::complex<double>, and PETSc should handle the linear algebra appropriately. All my code is realvalued, though; I'm not sure who's keeping the libMesh complex number support up to date.  Roy Stogner   Michael Povolotskyi, Ph.D. University of Rome "Tor Vergata" Department of Electronic Engineering Viale Politecnico, 1  00133 Rome  Italy Phone + 39 06 72597781 Fax + 39 06 2020519 http://www.optolab.uniroma2.it/pages/moshe/moshe.html <http://www.optolab.uniroma2.it/pages/moshe/moshe.html>;   This SF.net email is sponsored by: Splunk Inc. Do you grep through log files for problems? Stop! Download the new AJAX search engine that makes searching your log files as easy as surfing the web. DOWNLOAD SPLUNK! http://ads.osdn.com/?ad_id=7637&alloc_id=16865&op=click _______________________________________________ Libmeshusers mailing list Libmeshusers@... https://lists.sourceforge.net/lists/listinfo/libmeshusers 
From: Steffen Petersen <steffen.petersen@tu...>  20051215 12:07:46

The SLEPc interface in libmesh currently supports only standart eigenvalue problems (see example 16), but we have started to extend it for generalized problems (real and complex) about two weeks ago. In the next days I will commit the necessary changes. As it was already said, you will need SLEPc for solvin the eigen system. Since SLEPc builds up on PETSc, you will need corresponding versions of the two. I have been still using versions 2.2.1 and I have to admit, that I have not checked if everything works fine with the latest version 2.3.0. If you give me some time I will test the latest SLEPc releas together with libMesh and commit necessary changes together with the support for generalized problems. Steffen > You might want to check out SLEPc, an interface on top op > PETSc specifically for Eigenvalue problems. Stefan added an > interface to it from libMesh some time ago, and he might have > some comments on this thread too. > > Ben > > ________________________________ > > From: libmeshusersadmin@... > [mailto:libmeshusersadmin@...] On Behalf > Of Michael Povolotskyi > Sent: Wednesday, December 14, 2005 12:22 PM > To: Roy Stogner; libmesh  ML > Subject: Re: [Libmeshusers] Eigenvalue problem > > > 1) Yes, I mean Hx = gSx, sorry for the error. > 2) Does it mean that if one wants to use Libmesh just for one > complex problem, then all the other problems also have to be > complex? > > thank you, > Michael. > > > > Roy Stogner wrote: > > On Wed, 14 Dec 2005, Michael Povolotskyi wrote: > > > > I have to solve an eigenvalue problem for a > quantum physics calculations. > My questions are: > 1) Is it possible to solve a general eigenvalue > problem like Hx = Sx, > where H and S are known matrixes. > > > > Are you sure you don't mean Hx = gSx, where H and S are > known but g is > unknown? That's the generalized eigenvalue problem > built into SLEPc, > which is currently the only eigenvalue solve libMesh > interfaces with. > Our SLEPc support currently only handles the simple Hx > = gx problem, > and a new interface would have to be written to get generalized > eigenvalues. > > > > 2) Is it possible to have complex > (selfconjugated) matrixes? > > > > If both PETSc and libMesh have been compiled with > complex number > support on, then the default PetscScalar and libMesh > Number types will > both be std::complex<double>, and PETSc should handle > the linear > algebra appropriately. All my code is realvalued, > though; I'm not > sure who's keeping the libMesh complex number support > up to date. >  > Roy Stogner > > > > > >  >  > Michael Povolotskyi, Ph.D. > University of Rome "Tor Vergata" > Department of Electronic Engineering > Viale Politecnico, 1  00133 Rome  Italy > > Phone + 39 06 72597781 > Fax + 39 06 2020519 > http://www.optolab.uniroma2.it/pages/moshe/moshe.html >  > >  This > SF.net email is sponsored by: Splunk Inc. Do you grep through > log files for problems? Stop! Download the new AJAX search > engine that makes searching your log files as easy as surfing > the web. DOWNLOAD SPLUNK! > http://ads.osdn.com/?ad_id=7637&alloc_id=16865&op=click > _______________________________________________ Libmeshusers > mailing list Libmeshusers@... > https://lists.sourceforge.net/lists/listinfo/libmeshusers > 