Re: NMinimize Bug in Mathematica 7.0?
- To: mathgroup at smc.vnet.net
- Subject: [mg96270] Re: NMinimize Bug in Mathematica 7.0?
- From: dh <dh at metrohm.com>
- Date: Tue, 10 Feb 2009 05:55:01 -0500 (EST)
- References: <gmp0pi$c02$1@smc.vnet.net>
Hi,
it is common for numerical routines to create such problems. The reason
is, that a numerical routine can never sample the whole definition
region. However, it is a bit astonishing that NMinimize alreday fails
with this small problem. Maybe you want to ask Wolfram what they think
about this.
Daniel
appris at att.net wrote:
> Here is an example from Mathematica's user's guide:
>
> In[8]:= NMinimize[x^4 - 3 x^2 + x, x]
>
> Out[8]= {-3.513905039, {x -> -1.300839566}}
>
> however, trying to replicate it, I get the following:
>
> In[2]:= NMinimize[x^4 - 3 x^2 + x, x]
>
> Out[2]= {-1.070230182, {x -> 1.130901122}}
>
> One way to find the global min, I had to use a constraint such as x<0.
>
> Has anyone come across such a problem?
>
> In[3]:= $Version
>
> Out[3]= "7.0 for Microsoft Windows (32-bit) (November 10, 2008)"
>
> Thanks.
>