Services & Resources / Wolfram Forums
-----
 /
MathGroup Archive
2006
*January
*February
*March
*April
*May
*June
*July
*August
*September
*October
*November
*December
*Archive Index
*Ask about this page
*Print this page
*Give us feedback
*Sign up for the Wolfram Insider

MathGroup Archive 2006

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

Search the Archive

Re: How can I get this spiked Integral evaluated???

  • To: mathgroup at smc.vnet.net
  • Subject: [mg71977] Re: How can I get this spiked Integral evaluated???
  • From: dh <dh at metrohm.ch>
  • Date: Thu, 7 Dec 2006 06:25:19 -0500 (EST)

Hi,
your problem has nothing to do with oscillations. It is simply hard to 
find numrically your peak in such a large range. Therefore, you must 
specify more initial sample points:
NIntegrate[Exp[-x^2], {x, -900, 1000}, GaussPoints -> 100]
Daniel

Zeno wrote:
 > This is an integral with a spike that is not in the middle of the
 > integral range. Here is the integral...
 >
 > NIntegrate[Exp[-x^2], {x, -900, 1000}]
 >
 > Mathemtaica 5.2.2 gives this error message....
 >
 >  "Numerical \integration stopping due to loss of precision. Achieved
 > neither the requested \PrecisionGoal nor AccuracyGoal; suspect one of
 > the following: highly \oscillatory integrand or the true value of the
 > integral is 0. If your \integrand is oscillatory on a (semi-)infinite
 > interval try using the option \Method->Oscillatory in NIntegrate. More?
 >
 > However, to use the option "Method->Oscillatory" one of the bounds of
 > the integral must be infinity, so that would not work here. How do I
 > get it to to the integral in the range -900 to 1000??
 > The correct answer is 1.77245.
 >



  • Prev by Date: Re: Histogram3D
  • Next by Date: Re: How can I get this spiked Integral evaluated???
  • Previous by thread: Re: How can I get this spiked Integral evaluated???
  • Next by thread: Re: How can I get this spiked Integral evaluated???