# HG changeset patch
# User Rik <rik@octave.org>
# Date 1389835313 28800
# Node ID 61dab64aa5a687a995add5e99b2d085747ab84c1
# Parent  906e95708ec1932a5af35837fa2607aa684c8ff4
fminbnd.m: Correctly handle certain functions with odd discontinuities (bug #36923)

* fminbnd.m: Correctly get a minimum result even for functions with
specifically placed discontinuities which were defeating the Golden Section
search.  Add a %!test which verifies the behavior.

diff --git a/scripts/optimization/fminbnd.m b/scripts/optimization/fminbnd.m
--- a/scripts/optimization/fminbnd.m
+++ b/scripts/optimization/fminbnd.m
@@ -170,7 +170,7 @@
 
     ## update  a, b, v, w, and x
 
-    if (fu <= fval)
+    if (fu < fval)
       if (u < x)
         b = x;
       else
@@ -283,4 +283,5 @@
 %!assert (fminbnd (@(x) (x - 1e-3)^4, -1, 1, opt0), 1e-3, 10e-3*sqrt (eps))
 %!assert (fminbnd (@(x) abs (x-1e7), 0, 1e10, opt0), 1e7, 10e7*sqrt (eps))
 %!assert (fminbnd (@(x) x^2 + sin (2*pi*x), 0.4, 1, opt0), fzero (@(x) 2*x + 2*pi*cos (2*pi*x), [0.4, 1], opt0), sqrt (eps))
+%!assert (fminbnd (@(x) x > 0.3, 0, 1) < 0.3)