[Octave-bug-tracker] [bug #45944] eig(X, 'nobalance') does not exist in Octave vs. Matlab

[Nir Krakauer]

Follow-up Comment #4, bug #45944 (project octave):

You can try looking at [1], which gives some examples (involving larger
matrices) where balancing influences the answer noticeably.

Also, Octave's current eig function [2] has a test case where balancing
changes the answer (albeit probably only by something on the order of roundoff
error):

## "balance" is always default
## so the results with and without "balance" should be the same
## while in this case "nobalance" should produce different result
%!test
%! A = [3 -2 -0.9 0; -2 4 1 -0; -0 0 -1 0; -0.5 -0.5 0.1 1];
%! [V1, D1] = eig (A);
%! [V2, D2] = eig (A, "balance");
%! [V3, D3] = eig (A, "nobalance");
%! assert (V1, V2)
%! assert (D1, D2)
%! assert (isequal (V2, V3), false)

[1] http://www.sci.wsu.edu/math/faculty/watkins/pdfiles/balbad.pdf
[2] https://hg.savannah.gnu.org/hgweb/octave/file/tip/libinterp/corefcn/eig.cc

    _______________________________________________________

Reply to this item at:

  <https://savannah.gnu.org/bugs/?45944>

_______________________________________________
  Message sent via Savannah
  https://savannah.gnu.org/