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[Octave-bug-tracker] [bug #53719] eigs delivers wrong result in case of
From: |
Dan Sebald |
Subject: |
[Octave-bug-tracker] [bug #53719] eigs delivers wrong result in case of complex valued general eigenvalue problem |
Date: |
Thu, 26 Apr 2018 04:53:47 -0400 (EDT) |
User-agent: |
Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:55.0) Gecko/20100101 Firefox/55.0 |
Follow-up Comment #12, bug #53719 (project octave):
OK, the invalid number of converged Ritz makes sense.
I'm wondering about the following comment in the code:
c %-----------------------------------------%
c | Perform y <-- OP*x = inv[A-sigma*M]*M*x |
c | M*x has been saved in workd(ipntr(3)). |
c | The user only need the linear system |
c | solver here that takes workd(ipntr(3)) |
c | as input, and returns the result to |
c | workd(ipntr(2)). |
c %-----------------------------------------%
The documentation says that when IDO=1:
c Mode 3: A*x = lambda*M*x, M symmetric semi-definite
c ===> OP = inv[A - sigma*M]*M and B = M.
c ===> shift-and-invert mode
c If OP*x = amu*x, then lambda = sigma + 1/amu.
[snip]
c IDO = 1: compute Y = OP * Z and Z = B * X where
c IPNTR(1) is the pointer into WORKD for X,
c IPNTR(2) is the pointer into WORKD for Y,
c IPNTR(3) is the pointer into WORKD for Z.
That comment above makes it sound as though Z = M X, but then why would the
documentation state Y = OP Z? That would be Y = inv(A) M M X. I don't follow
that part of things.
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- [Octave-bug-tracker] [bug #53719] eigs delivers wron result in case of complex valued general eigenvalue problem, (continued)
- [Octave-bug-tracker] [bug #53719] eigs delivers wron result in case of complex valued general eigenvalue problem, Marco Caliari, 2018/04/23
- [Octave-bug-tracker] [bug #53719] eigs delivers wron result in case of complex valued general eigenvalue problem, Rik, 2018/04/23
- [Octave-bug-tracker] [bug #53719] eigs delivers wrong result in case of complex valued general eigenvalue problem, Rik, 2018/04/23
- [Octave-bug-tracker] [bug #53719] eigs delivers wrong result in case of complex valued general eigenvalue problem, Marco Caliari, 2018/04/24
- [Octave-bug-tracker] [bug #53719] eigs delivers wrong result in case of complex valued general eigenvalue problem, John W. Eaton, 2018/04/24
- [Octave-bug-tracker] [bug #53719] eigs delivers wrong result in case of complex valued general eigenvalue problem, Rik, 2018/04/24
- [Octave-bug-tracker] [bug #53719] eigs delivers wrong result in case of complex valued general eigenvalue problem, Marco Caliari, 2018/04/25
- [Octave-bug-tracker] [bug #53719] eigs delivers wrong result in case of complex valued general eigenvalue problem, Dan Sebald, 2018/04/25
- [Octave-bug-tracker] [bug #53719] eigs delivers wrong result in case of complex valued general eigenvalue problem, Marco Caliari, 2018/04/26
- [Octave-bug-tracker] [bug #53719] eigs delivers wrong result in case of complex valued general eigenvalue problem, Marco Caliari, 2018/04/26
- [Octave-bug-tracker] [bug #53719] eigs delivers wrong result in case of complex valued general eigenvalue problem,
Dan Sebald <=
- [Octave-bug-tracker] [bug #53719] eigs delivers wrong result in case of complex valued general eigenvalue problem, Marco Caliari, 2018/04/26
- [Octave-bug-tracker] [bug #53719] eigs delivers wrong result in case of complex valued general eigenvalue problem, Marco Caliari, 2018/04/26
- [Octave-bug-tracker] [bug #53719] eigs delivers wrong result in case of complex valued general eigenvalue problem, Dan Sebald, 2018/04/26
- [Octave-bug-tracker] [bug #53719] eigs delivers wrong result in case of complex valued general eigenvalue problem, Marco Caliari, 2018/04/27
- [Octave-bug-tracker] [bug #53719] eigs delivers wrong result in case of complex valued general eigenvalue problem, Dan Sebald, 2018/04/27