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[Octave-bug-tracker] [bug #57185] svds returns inconsistent singular val
From: |
Rik |
Subject: |
[Octave-bug-tracker] [bug #57185] svds returns inconsistent singular values |
Date: |
Fri, 8 Nov 2019 16:25:57 -0500 (EST) |
User-agent: |
Mozilla/5.0 (Windows NT 10.0; WOW64; Trident/7.0; rv:11.0) like Gecko |
Follow-up Comment #8, bug #57185 (project octave):
For the second question, I think we need to check the code. In svds.m there
is
if (nargout > 1)
[V, s, flag] = eigs ([sparse(m,m), b; b', sparse(n,n)],
b_k, b_sigma, b_opts);
s = diag (s);
else
s = eigs ([sparse(m,m), b; b', sparse(n,n)], b_k, b_sigma, b_opts);
endif
so we are calling eigs with a different function prototype in each case. I
seem to recall that if only the singular values are requested we may perform a
sort on them to ensure uniform ordering. But, we can't do that arbitrarily
when someone has requested the full decomposition because it would also
require changing the U and V matrices to ensure that the decomposition
A = U * S * V'
still holds.
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- [Octave-bug-tracker] [bug #57185] svd returns inconsistent eigenvalues, Muhali, 2019/11/07
- [Octave-bug-tracker] [bug #57185] svd returns inconsistent eigenvalues, Mike Miller, 2019/11/07
- [Octave-bug-tracker] [bug #57185] svd returns inconsistent eigenvalues, Rik, 2019/11/07
- [Octave-bug-tracker] [bug #57185] svd returns inconsistent eigenvalues, Dmitri A. Sergatskov, 2019/11/07
- [Octave-bug-tracker] [bug #57185] svd returns inconsistent eigenvalues, Kai Torben Ohlhus, 2019/11/07
- [Octave-bug-tracker] [bug #57185] svd returns inconsistent eigenvalues, Muhali, 2019/11/08
- [Octave-bug-tracker] [bug #57185] svds returns inconsistent singular values, Kai Torben Ohlhus, 2019/11/08
- [Octave-bug-tracker] [bug #57185] svds returns inconsistent singular values, Rik, 2019/11/08
- [Octave-bug-tracker] [bug #57185] svds returns inconsistent singular values,
Rik <=
- [Octave-bug-tracker] [bug #57185] svds returns inconsistent singular values, Rik, 2019/11/08
- [Octave-bug-tracker] [bug #57185] svds returns inconsistent singular values, Rik, 2019/11/09
- [Octave-bug-tracker] [bug #57185] svds returns inconsistent singular values, Rik, 2019/11/09
- [Octave-bug-tracker] [bug #57185] svds returns inconsistent singular values, Rik, 2019/11/09
- [Octave-bug-tracker] [bug #57185] eigs does not consistently order eigenvalues, Rik, 2019/11/09
- [Octave-bug-tracker] [bug #57185] eigs does not consistently order eigenvalues, Rik, 2019/11/14
- [Octave-bug-tracker] [bug #57185] eigs does not consistently order eigenvalues, Rik, 2019/11/14
- [Octave-bug-tracker] [bug #57185] eigs does not consistently order eigenvalues, Rik, 2019/11/14
- [Octave-bug-tracker] [bug #57185] eigs does not consistently order eigenvalues, Rik, 2019/11/14
- [Octave-bug-tracker] [bug #57185] eigs does not consistently order eigenvalues, Rik, 2019/11/14