       Re: Weird NMinimize behaviour

• To: mathgroup at smc.vnet.net
• Subject: [mg97570] Re: [mg97518] Weird NMinimize behaviour
• From: DrMajorBob <btreat1 at austin.rr.com>
• Date: Sun, 15 Mar 2009 05:30:30 -0500 (EST)
• References: <200903142313.SAA25117@smc.vnet.net>
• Reply-to: drmajorbob at bigfoot.com

```=CF=80

???

Post readable code. Use Edit>Copy As>Plain Text and paste into e-mail.

Bobby

On Sat, 14 Mar 2009 18:13:15 -0500, Filippo Miatto <miatto at gmail.com>
wrote:

> Dear all,
> i'm working in the quantum optics group of the university of Leiden,
> and i use mathematica 7 a lot.
> we have both windows machines and macs. On a mac i was trying to
> minimize the function
>
> j[s_] := Sum[F2[n1, k1, n2, k2], {n1, 0, 2 s - 1}, {k1, 0, 2 s - 1},
> {n2, 0,2s - 1}, {k2, 0, 2s - 1}] + R2[s]
>
> Where
> R2[s_] := (1 - 1/=CF=80 Sum[(-1)^(n1 + 1) Subscript[z, n1], {n1, 1, 2 s -
> 1}])^4
>
> and
> F2[n1_, k1_, n2_, k2_] := (-1)^(n1 + k1 + n2 + k2)/(360 =CF=80^4) (8
> =CF=80^4 -
> 60 =CF=80^2 Mod[-Subscript[z, k1] + Subscript[z, n1] - Subscript[z, k2] +
> Subscript[z, n2], 2 =CF=80]^2 + 60 =CF=80 Mod[-Subscript[z, k1] +
> Subscript[z,
> n1] - Subscript[z, k2] + Subscript[z, n2], 2 =CF=80]^3 -15 Mod[-
> Subscript[z, k1] + Subscript[z, n1] - Subscript[z, k2] +  Subscript[z,
> n2], 2 =CF=80]^4)
>
> (sorry for the mess, on the screen the subscripts simply appear as
> subscripts...)
>
> and i get certain results for s=1,2,3,4,5,etc..
> on the windows machine though, i get worse results! the version of
> mathematica is the same, machineprecision value is the same, even
> the .nb file is the same! (the processor is different: a dualcore2duo
> on the mac and a quad core xeon on the windows machine)
> The mac can work well until s=6, the windows machine can go on to
> greater values, but still giving less good results.
> Do you have any idea how i can solve this issue?
> Thank you in advance!
> Filippo=
>

--
DrMajorBob at bigfoot.com

```

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