fsolve problem

[Rolf Fabian]

For functions like e.g.
     F = "x(1).^19 + x(2).^19 - 1"
fsolve returns output x == input x0 as well as successful
iteration  flag (info =1) despite the fact that
fval(1) > 10^15 which is definitely far from zero.

BTW 
Why is 'fval' not a scalar ?
What is the meaning of the 2nd element of 'fval'?

Why is a column vector x returned
despite the fact that initialization is
done by a row vector ?

Cannot find anything about those
questions in documentation.

Rolf Fabian
<r dot fabian at jacobs-university dot de>


Follow by:
octave-3.0.0.exe:> computer, version
i686-pc-msdosmsvc
ans = 3.0.0

octave-3.0.0.exe:> format long
octave-3.0.0.exe:> [x,fval,info]  =  fsolve( F="x(1).^19+x(2).^19 - 1", x0=
rand(1,2)*10)
x =
   4.48467415438827
   6.75774358978933

fval =
   5.83998986277861e+015          # < --- !!!
   4.69824018802541e-294

info =  1                                     # < --- !!!

octave-3.0.0.exe:> eval(F)
ans = 5.83998986277861e+015   # < --- !!!

octave-3.0.0.exe:> x0
x0 =
   4.48467415438827   6.75774358978933

octave-3.0.0.exe:> x0.' - x
ans =
   0
   0

-----
Rolf Fabian
<r dot fabian at jacobs-university dot de>

-- 
View this message in context: http://www.nabble.com/fsolve-problem-tp15586014p15586014.html
Sent from the Octave - Bugs mailing list archive at Nabble.com.