Mercurial > hg > octave-lyh
changeset 10337:7c97da90fc8f
check for discontinuities in fzero
| author | Rik <rdrider0-list@yahoo.com> |
|---|---|
| date | Fri, 19 Feb 2010 07:06:36 +0100 |
| parents | 1603dfe72933 |
| children | 21dd58bd683c |
| files | scripts/ChangeLog scripts/optimization/fzero.m |
| diffstat | 2 files changed, 15 insertions(+), 0 deletions(-) [+] |
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--- a/scripts/ChangeLog +++ b/scripts/ChangeLog @@ -1,3 +1,7 @@ +2010-02-19 Rik <octave@nomad.inbox5.com> + + * optimization/fzero.m: Add test for discontinuity at the end. + 2010-02-18 John W. Eaton <jwe@octave.org> * image/imfinfo.m: Don't handle file time stamp here.
--- a/scripts/optimization/fzero.m +++ b/scripts/optimization/fzero.m @@ -38,6 +38,8 @@ ## Maximum number of iterations or function evaluations has been exhausted. ## @item -1 ## The algorithm has been terminated from user output function. +## @item -5 +## The algorithm may have converged to a singular point. ## @end itemize ## @seealso{optimset, fsolve} ## @end deftypefn @@ -133,6 +135,8 @@ error ("fzero:bracket", "fzero: not a valid initial bracketing"); endif + slope0 = (fb - fa) / (b - a); + itype = 1; if (abs (fa) < abs (fb)) @@ -281,6 +285,13 @@ endif endwhile + ## Check solution for a singularity by examining slope + if (info == 1) + if ((b - a) != 0 && abs ((fb - fa)/(b - a) / slope0) > max (1e6, 0.5/tolx)) + info = -5; + endif + endif + output.iterations = niter; output.funcCount = nfev; output.bracket = [a, b];