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Re: Quite Upset with NIntegrate

• To: mathgroup at smc.vnet.net
• Subject: [mg54180] Re: [mg54142] Quite Upset with NIntegrate
• From: yehuda ben-shimol <bsyehuda at gmail.com>
• Date: Sat, 12 Feb 2005 01:58:37 -0500 (EST)
• References: <200502110834.DAA09269@smc.vnet.net>
• Reply-to: yehuda ben-shimol <bsyehuda at gmail.com>
• Sender: owner-wri-mathgroup at wolfram.com

It is difficult to comment without seeing the details. Is there any
way we can see it?
yehuda

On Fri, 11 Feb 2005 03:34:40 -0500 (EST), I. Turan
<ituran at bohr.concordia.ca> wrote:
> Hi:
> 
> I have been trying to evaluate a 4-dimensional integral by using
> NIntegrate with Mathematica 4 w2k.  The integrand and even the
> integration limits are quite complicated (depending on int.
> variables). The length of the integrand is around 2000 lines in the
> FortranForm.
> 
> If I don't play with any options of NIntegrate, It takes one day to
> get one data point and gives very  unreasonably weird values. By
> setting, however, MaxPoints something like 100000 it is possible to
> get faster results but still it seems that Mathematica couldn't handle
> it. When I draw a figure from these data points, it appears very very
> spiky such that it is even not possible to fit the curve. However, it
> is supposed to be very smooth.
> 
> Should I accept that Mathematica can not handle such a
> numerical integration or is there a way to make Nintegrate working
> better?
> 
> Thanks a lot,
> 
> Ismail
> 
>

• References:
  • Quite Upset with NIntegrate
    • From: ituran@bohr.concordia.ca (I. Turan)