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## libmesh-users

 [Libmesh-users] Eigenvalue Solver From: David Xu - 2006-02-20 22:48:43 Hi Steffen and Ondrej, I read your previous message that you've extended the slepc interface to support generalized eigen problems. I'd like to get the details from you. I'm new to libmesh and I'm wondering if you can post some new tutorial examples on how to solve eigen problems using libmesh (eg. solve 1D or 2D simple harmonic oscillator)? That will a great help. Ondrej, I read about your message about your implementation of libmesh and pysparse's jacobi-davidson solver. That sounds really good. Could you please give me the details too? I really appreciate it. David
 [Libmesh-users] AW: Eigenvalue Solver From: Steffen Petersen - 2006-02-21 18:28:34 Hello David, I will commit an adjusted example within the next days. Note that some rather useful functionality is only available with the latest slepc version (e.g. computation of the smallest eigenvalues within the spectrum), so I recommend to use the 2.3.0 versions of petsc and slepc. Steffen > Hi Steffen and Ondrej, > > I read your previous message that you've extended the slepc interface > to support generalized eigen problems. I'd like to get the details > from you. I'm new to libmesh and I'm wondering if you can post some > new tutorial examples on how to solve eigen problems using libmesh > (eg. solve 1D or 2D simple harmonic oscillator)? That will a great > help. > > Ondrej, I read about your message about your implementation of libmesh > and pysparse's jacobi-davidson solver. That sounds really good. Could > you please give me the details too? I really appreciate it. > > David >
 [Libmesh-users] Re: Eigenvalue Solver From: Steffen Petersen - 2006-02-27 08:33:35 I have just committed an example 17 including a generalized eigenvalue problem. Currently, the largest eigenvalues in the spectrum are computed. The code can be easily changed in order to compute the smallest values (or use the slepc comman line options). However, the Lanczos solver slepc offers with this option appears to be somewhat unstable when used to compute the smallest values (perhaps this is due to the zero eigenmode in this example). An option to work around this problem is to configure and install slepc with arpack and parpack (the arpack solver works fine for example 17). Steffen David Xu schrieb: > Hi Steffen and Ondrej, > > I read your previous message that you've extended the slepc interface > to support generalized eigen problems. I'd like to get the details > from you. I'm new to libmesh and I'm wondering if you can post some > new tutorial examples on how to solve eigen problems using libmesh > (eg. solve 1D or 2D simple harmonic oscillator)? That will a great > help. > > Ondrej, I read about your message about your implementation of libmesh > and pysparse's jacobi-davidson solver. That sounds really good. Could > you please give me the details too? I really appreciate it. > > David
 [Libmesh-users] Re: Eigenvalue Solver From: David Xu - 2006-03-01 18:59:50 Hi Steffen, I'm looking forward to your example 17 and implementation of generalized eigen value solver with libmesh. Thanks, David On 2/27/06, Steffen Petersen wrote: > I have just committed an example 17 including a generalized > eigenvalue problem. Currently, the largest eigenvalues > in the spectrum are computed. The code can be easily changed > in order to compute the smallest values (or use the slepc comman > line options). However, the Lanczos solver slepc offers with this > option appears to be somewhat unstable when used to compute > the smallest values (perhaps this is due to the zero eigenmode in > this example). An option to work around this problem is to > configure and install slepc with arpack and parpack (the arpack > solver works fine for example 17). > > Steffen > > > > David Xu schrieb: > > Hi Steffen and Ondrej, > > > > I read your previous message that you've extended the slepc interface > > to support generalized eigen problems. I'd like to get the details > > from you. I'm new to libmesh and I'm wondering if you can post some > > new tutorial examples on how to solve eigen problems using libmesh > > (eg. solve 1D or 2D simple harmonic oscillator)? That will a great > > help. > > > > Ondrej, I read about your message about your implementation of libmesh > > and pysparse's jacobi-davidson solver. That sounds really good. Could > > you please give me the details too? I really appreciate it. > > > > David > >
 [Libmesh-users] Re: Eigenvalue Solver From: David Xu - 2006-03-04 18:14:50 Hi Steffen, I'm not familiar with Slepc. Could elaborate how to modify the code or use command line options to calculate the smallest eigenvalues? Thanks, David On 2/27/06, Steffen Petersen wrote: > I have just committed an example 17 including a generalized > eigenvalue problem. Currently, the largest eigenvalues > in the spectrum are computed. The code can be easily changed > in order to compute the smallest values (or use the slepc comman > line options). However, the Lanczos solver slepc offers with this > option appears to be somewhat unstable when used to compute > the smallest values (perhaps this is due to the zero eigenmode in > this example). An option to work around this problem is to > configure and install slepc with arpack and parpack (the arpack > solver works fine for example 17). > > Steffen > > > > David Xu schrieb: > > Hi Steffen and Ondrej, > > > > I read your previous message that you've extended the slepc interface > > to support generalized eigen problems. I'd like to get the details > > from you. I'm new to libmesh and I'm wondering if you can post some > > new tutorial examples on how to solve eigen problems using libmesh > > (eg. solve 1D or 2D simple harmonic oscillator)? That will a great > > help. > > > > Ondrej, I read about your message about your implementation of libmesh > > and pysparse's jacobi-davidson solver. That sounds really good. Could > > you please give me the details too? I really appreciate it. > > > > David > >
 [Libmesh-users] Re: Eigenvalue Solver From: David Xu - 2006-03-06 08:17:22 Hi Steffen, Besides ARPACK, can I call other package (BLZPACK, PLANSO, and TRLAN) from libmesh that SLEPC has an interface to? Of course I will install them with SLEPC first. Thanks, David On 2/27/06, Steffen Petersen wrote: > I have just committed an example 17 including a generalized > eigenvalue problem. Currently, the largest eigenvalues > in the spectrum are computed. The code can be easily changed > in order to compute the smallest values (or use the slepc comman > line options). However, the Lanczos solver slepc offers with this > option appears to be somewhat unstable when used to compute > the smallest values (perhaps this is due to the zero eigenmode in > this example). An option to work around this problem is to > configure and install slepc with arpack and parpack (the arpack > solver works fine for example 17). > > Steffen > > > > David Xu schrieb: > > Hi Steffen and Ondrej, > > > > I read your previous message that you've extended the slepc interface > > to support generalized eigen problems. I'd like to get the details > > from you. I'm new to libmesh and I'm wondering if you can post some > > new tutorial examples on how to solve eigen problems using libmesh > > (eg. solve 1D or 2D simple harmonic oscillator)? That will a great > > help. > > > > Ondrej, I read about your message about your implementation of libmesh > > and pysparse's jacobi-davidson solver. That sounds really good. Could > > you please give me the details too? I really appreciate it. > > > > David > >