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Re: Problem with the GaussianQuadratureWeights[n, a, b]

• To: mathgroup at smc.vnet.net
• Subject: [mg26444] Re: Problem with the GaussianQuadratureWeights[n, a, b]
• From: Jens-Peer Kuska <kuska at informatik.uni-leipzig.de>
• Date: Thu, 21 Dec 2000 01:51:45 -0500 (EST)
• Organization: Universitaet Leipzig
• References: <91pjn3$5vp@smc.vnet.net>
• Sender: owner-wri-mathgroup at wolfram.com

Hi,

setting the precision will help and 

GaussianQuadratureWeights[42, 0, 1, 32]

work fine.

Cheng Liu wrote:
> 
> Hi,
> 
>         I accidently run into this strange behavior.  I am using the
> package NumericalMath`GaussianQuadrature` and the function
> GaussianQuadratureWeights[n, a, b] to obtain the abscissas and weights
> for the n-point Gaussian quadrature formula on the interval (a, b).
> The specific interval in my problem is (0, 1),  I noticed that
> when 40 <= n <= 50, if n is odd, the function gives correct answer,
> but when n is even, the function gives the following error message:
> 
> In[43]:=
> GaussianQuadratureWeights[42, 0, 1]
> \!\(Power::"infy" \(\(:\)\(\ \)\)
>      "Infinite expression \!\(1\/0.`\) encountered."\)
> \!\(Power::"infy" \(\(:\)\(\ \)\)
>      "Infinite expression \!\(1\/0.`\) encountered."\)
> \!\(Power::"infy" \(\(:\)\(\ \)\)
>      "Infinite expression \!\(1\/0.`\) encountered."\)
> General::stop :
>      Further output of Power::infy will be suppressed during this calculation.
> f::indet :
>      Indeterminate expression - 1672.96 + ComplexInfinity +
>        ComplexInfinity + \[LeftSkeleton]6\[RightSkeleton] + ComplexInfinity +
>        ComplexInfinity encountered.
SNIPP SNAPP
> Thanks.
> 
> Cheng
> --

• Follow-Ups:
  • Re: Re: Problem with the GaussianQuadratureWeights[n, a, b]
    • From: Cheng Liu <cliu@lanl.gov>