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[Octave-bug-tracker] [bug #53700] eigs test failure related to ARPACK ge
From: |
Dan Sebald |
Subject: |
[Octave-bug-tracker] [bug #53700] eigs test failure related to ARPACK generating real NaN rather than complex NaN+1i*NaN |
Date: |
Fri, 20 Apr 2018 04:29:01 -0400 (EDT) |
User-agent: |
Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:59.0) Gecko/20100101 Firefox/59.0 |
Follow-up Comment #14, bug #53700 (project octave):
@Marco: Good suggestion. I reached a similar conclusion because I think there
isn't anything wrong with setting up the routines. It is simply that the
library function is behaving slightly different in terms of convergence:
F77_INT k0 = k; // original number of eigenvalues required
F77_FUNC (dneupd, DNEUPD)
(rvec77, F77_CONST_CHAR_ARG2 ("A", 1), sel, dr, di, z, n, sigmar,
sigmai, workev, F77_CONST_CHAR_ARG2 (&bmat, 1), n,
F77_CONST_CHAR_ARG2 ((typ.c_str ()), 2), k, tol, presid, p, v, n,
iparam,
ipntr, workd, workl, lwork, info2 F77_CHAR_ARG_LEN(1)
F77_CHAR_ARG_LEN(1)
F77_CHAR_ARG_LEN(2));
// On exit, if (and only if) rvec == true, k may have been increased by one
// and be equal to ip(4), see dngets.
std::cerr << "ip(4) = " << ip(4) << "\n";
if (! rvec && ip(4) > k)
k = ip(4);
ip(4) is 1, not 3 in my case. It could be that convergence of the first one
is solid, but the other two are tenuous and dependent on the compiler.
Looking at what Mike listed:
>> imag(d)
ans =
0.0000e+00
-8.6837e-13
8.6837e-13
NaN
NaN
NaN
NaN
NaN
NaN
NaN
if only that first eigenvalue is examined, then the followup code that checks
for the imaginary component is not going to set "have_cplx_eig = true;". It's
only the second and third cases where have_cplx_eig is set true in Mike's
case.
In addition to the isreal() check, how about testing that d(1) == 1.0 or
(1.0,0.0) in addition to the check on d(10)? It seems that's the reliable
eigenvalue.
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- [Octave-bug-tracker] [bug #53700] eigs test failure related to ARPACK generating real NaN rather than complex NaN+1i*NaN, (continued)
- [Octave-bug-tracker] [bug #53700] eigs test failure related to ARPACK generating real NaN rather than complex NaN+1i*NaN, Mike Miller, 2018/04/19
- [Octave-bug-tracker] [bug #53700] eigs test failure related to ARPACK generating real NaN rather than complex NaN+1i*NaN, Dan Sebald, 2018/04/19
- [Octave-bug-tracker] [bug #53700] eigs test failure related to ARPACK generating real NaN rather than complex NaN+1i*NaN, Mike Miller, 2018/04/19
- [Octave-bug-tracker] [bug #53700] eigs test failure related to ARPACK generating real NaN rather than complex NaN+1i*NaN, Dan Sebald, 2018/04/19
- [Octave-bug-tracker] [bug #53700] eigs test failure related to ARPACK generating real NaN rather than complex NaN+1i*NaN, Dmitri A. Sergatskov, 2018/04/19
- [Octave-bug-tracker] [bug #53700] eigs test failure related to ARPACK generating real NaN rather than complex NaN+1i*NaN, Mike Miller, 2018/04/19
- [Octave-bug-tracker] [bug #53700] eigs test failure related to ARPACK generating real NaN rather than complex NaN+1i*NaN, Mike Miller, 2018/04/19
- [Octave-bug-tracker] [bug #53700] eigs test failure related to ARPACK generating real NaN rather than complex NaN+1i*NaN, Mike Miller, 2018/04/19
- [Octave-bug-tracker] [bug #53700] eigs test failure related to ARPACK generating real NaN rather than complex NaN+1i*NaN, Mike Miller, 2018/04/20
- [Octave-bug-tracker] [bug #53700] eigs test failure related to ARPACK generating real NaN rather than complex NaN+1i*NaN, Marco Caliari, 2018/04/20
- [Octave-bug-tracker] [bug #53700] eigs test failure related to ARPACK generating real NaN rather than complex NaN+1i*NaN,
Dan Sebald <=
- [Octave-bug-tracker] [bug #53700] eigs test failure related to ARPACK generating real NaN rather than complex NaN+1i*NaN, Marco Caliari, 2018/04/20
- [Octave-bug-tracker] [bug #53700] eigs test failure related to ARPACK generating real NaN rather than complex NaN+1i*NaN, Dan Sebald, 2018/04/20
- [Octave-bug-tracker] [bug #53700] eigs test failure related to ARPACK generating real NaN rather than complex NaN+1i*NaN, Dan Sebald, 2018/04/20
- [Octave-bug-tracker] [bug #53700] eigs test failure related to ARPACK generating real NaN rather than complex NaN+1i*NaN, Mike Miller, 2018/04/20
- [Octave-bug-tracker] [bug #53700] eigs test failure related to ARPACK generating real NaN rather than complex NaN+1i*NaN, Dan Sebald, 2018/04/20
- [Octave-bug-tracker] [bug #53700] eigs test failure related to ARPACK generating real NaN rather than complex NaN+1i*NaN, Dan Sebald, 2018/04/20
- [Octave-bug-tracker] [bug #53700] eigs test failure related to ARPACK generating real NaN rather than complex NaN+1i*NaN, Dmitri A. Sergatskov, 2018/04/20
- [Octave-bug-tracker] [bug #53700] eigs test failure related to ARPACK generating real NaN rather than complex NaN+1i*NaN, Dan Sebald, 2018/04/22
- [Octave-bug-tracker] [bug #53700] eigs test failure related to ARPACK generating real NaN rather than complex NaN+1i*NaN, Dmitri A. Sergatskov, 2018/04/22
- [Octave-bug-tracker] [bug #53700] eigs test failure related to ARPACK generating real NaN rather than complex NaN+1i*NaN, Marco Caliari, 2018/04/23