Services & Resources / Wolfram Forums / MathGroup Archive
-----

MathGroup Archive 2012

[Date Index] [Thread Index] [Author Index]

Search the Archive

Re: numerical integration

  • To: mathgroup at smc.vnet.net
  • Subject: [mg125919] Re: numerical integration
  • From: Bill Rowe <readnews at sbcglobal.net>
  • Date: Sat, 7 Apr 2012 05:55:37 -0400 (EDT)
  • Delivered-to: l-mathgroup@mail-archive0.wolfram.com

On 4/6/12 at 5:52 AM, eladarbel at hotmail.com (Elad) wrote:


>Im little bit confused, but can it be that those different method
>gives completely different answers??

>IntegrationResult[7, 0.1]

>and

>With[{\[Lambda] = 7, \[Epsilon] = 0.1}...

>[Im new here so its also possible i have no idea what im talking
>about]

I cannot give you a definitive answer without more details of
what you are doing. The snippets of code you posted above simply
aren't sufficient.

There are a number of possible reasons for different methods to
give different answers. Different methods might use different
algorithms which might have different error propagation characteristics.

Internal time constraints might cause apparently different
answers from different methods.

Mathematica caches intermediate results from many computations.
A second computation could make use of the cached results
allowing for further refinement of the answer from the first
computation resulting in apparently different answers.

Complex answers from problems often appear quite different but
are mathematically equivalent.

Which if any of these explains your particular issue will depend
on details of your issue you have not provided.




  • Prev by Date: Re: subgraph error (errata)
  • Next by Date: Re: Why does MemberQ[{0,1,2}, expr_] evaluate to True?
  • Previous by thread: Re: numerical integration
  • Next by thread: Graphics3D and transparent background