[Octave-bug-tracker] [bug #53700] eigs test failure related to ARPACK generating real NaN rather than complex NaN+1i*NaN

[Dan Sebald]

Follow-up Comment #30, bug #53700 (project octave):

The warning can be turned off with:


warning ("off", "Octave:eigs:UnconvergedEigenvalues", "local");


So the suggestion of


+%! d = eigs (A, floor((length(A)-1)/2), "sm", opts);


won't work.  How about floor(length(A)/4) rather than floor((length(A)-1)/2)? 
That would put the NEV somewhere in the middle of the range where the Krylov
subspace isn't adequate.

It's up to Marco to make the choice.  Check for real/imaginary or pick an NEV
somewhere that generates lots of 1.0+-iZi and NaN+iNaN.  Probably doesn't
matter too much.  We're seeing so much variation in the convergence behavior
for all the different libraries and compilers out there.

    _______________________________________________________

Reply to this item at:

  <http://savannah.gnu.org/bugs/?53700>

_______________________________________________
  Message sent via/by Savannah
  http://savannah.gnu.org/