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Author Comment/Response
Bruce
02/07/13 5:23pm

In Response To 'Re: Re: Problem with NIntegrate'
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The primary problem is that the function being integrated has many sharp corners and NIntegrate has difficulty putting smooth surfaces through them. When the wider domain (to 35 instead of to 28) is specified, the sampling points are spread out and some features are not sampled as well.

The early calculations and the IAAi function have a lot of machine-precision numbers. Running NIntegrate with higher WorkingPrecision
would require converting these coefficients to high-precision numbers (with SetPrecision or Rationalize). For example,

hIAAi[qq_, rr_] = SetPrecision[IAAi[qq, rr], 30]

NIntegrate[
hIAAi[s3, s1], {s3, imin, 8/10, 28},
       {s1, imin, 61/100, 976/1000, 35},
Method ->   "LocalAdaptive",
WorkingPrecision -> 20,
PrecisionGoal -> 10, AccuracyGoal -> 8]


(I admit that WorkingPrecision or 20 or 30 is much slower than the default WorkingPrecision.)

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Subject (listing for 'Problem with NIntegrate')
Author Date Posted
Problem with NIntegrate BB 01/18/13 1:57pm
Re: Problem with NIntegrate Forum Moder... 01/18/13 2:37pm
Re: Re: Problem with NIntegrate BB 02/02/13 9:17pm
Re: Re: Re: Problem with NIntegrate Bruce 02/07/13 5:23pm
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