diff -r 97b4bd6f0925 scripts/optimization/fzero.m
--- a/scripts/optimization/fzero.m	Sat Feb 13 08:17:21 2010 +0100
+++ b/scripts/optimization/fzero.m	Mon Feb 15 10:24:07 2010 -0800
@@ -36,10 +36,12 @@
 ## The algorithm converged to a solution.
 ## @item 0
 ## Maximum number of iterations or function evaluations has been exhausted.
 ## @item -1
 ## The algorithm has been terminated from user output function.
+## @item -2
+## The algorithm may have converged to a singular point.
 ## @end itemize
 ## @seealso{optimset, fsolve} 
 ## @end deftypefn
 
 ## This is essentially the ACM algorithm 748: Enclosing Zeros of
@@ -279,10 +281,17 @@
     if (itype == 2)
       mba = mu * (b - a);
     endif
   endwhile
 
+  ## Check solution for a singularity by examining slope
+  if (info == 1)
+    if ((b - a) != 0 && abs ((fb - fa)/(b - a)) > max (1e6, 0.5/tolx) )
+      info = -2;
+    endif
+  endif
+
   output.iterations = niter;
   output.funcCount = nfev;
   output.bracket = [a, b];
   output.bracketf = [fa, fb];