Mathematica 9 is now available
Services & Resources / Wolfram Forums / MathGroup Archive
-----

MathGroup Archive 2011

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

Search the Archive

Re: NInegrate Bug

  • To: mathgroup at smc.vnet.net
  • Subject: [mg116472] Re: NInegrate Bug
  • From: "Kurt TeKolste" <tekolste at fastmail.net>
  • Date: Wed, 16 Feb 2011 04:37:06 -0500 (EST)

Comforting, but expensive.  Do you have a patch for 7?

On Tue, 15 Feb 2011 23:17 +1100, "Andrew Moylan" <amoylan at wolfram.com>
wrote:
> Hi Kurt,
> 
> You should not encounter any problem in Mathematica 8. E.g.
> 
> In[1]:= NIntegrate[Sin[x^2], {x, -5, -2}]
> 
> Out[1]= -0.276859
> 
> In[2]:= N[Integrate[Sin[x^2], {x, -5, -2}]]
> 
> Out[2]= -0.276859
> 
> Andrew Moylan
> Wolfram Research
> 
> 
> 
> On Feb 15, 2011, at 10:34 PM, Kurt TeKolste wrote:
> 
> > Has there been a resolution of the NIntegrate bug?
> > 
> > Apparently NIntegrate produces the negative of the right answer for
> > integrations that start and end to the left of zero -- some of the time.
> > (Cos[x] and Sin[x^2] get the wrong result, Sin[x] is good).
> > 
> > Since it is not clear what criterion Mathematica uses in deciding to
> > give the wrong answer it is not clear when to use NIntegrate[] and when
> > to use NIntegrate[*Sign[independent variable]].
> > 
> > And this calls into question any results for analysis that uses
> > NIntegrate -- not a happy situation.
> > 
> > Kurt TeKolste
> > 
> 
> 


  • Prev by Date: Re: Replace elements in a matrix
  • Next by Date: Re: To put name to columns
  • Previous by thread: Re: NInegrate Bug
  • Next by thread: Re: NInegrate Bug