Re: Precision issues
- To: mathgroup at smc.vnet.net
- Subject: [mg73531] Re: Precision issues
- From: "Ray Koopman" <koopman at sfu.ca>
- Date: Wed, 21 Feb 2007 01:47:16 -0500 (EST)
- References: <erelv2$7ol$1@smc.vnet.net>
On Feb 20, 3:27 am, mickey <m... at hotmail.com> wrote:
> Hi,
>
> I am calculating certain integrals numerically and get back a number.
> Now, is it possible to determine how many digits is that answer accurate
> to?
>
> E.g.,
>
> NIntegrate[ Exp[-p^2 - q^2], {p, 0, 10}, {q, 0, 10}, Method ->
> MonteCarlo[24], MaxPoints -> 1000000]
>
> Gives,
>
> 0.791249
>
> How many digits is this answer accurate to?
>
> Thanks,
> -M
The correct answer (to six digits) is 0.785398,
so you have two acccurate digits.
>From the Mathematica Help Browser,
NIntegrate > Further Examples > MonteCarlo:
"If the AccuracyGoal and PrecisionGoal are set to Automatic, they
will be set to 2 in the methods MonteCarlo and QuasiMonteCarlo,
and to 6 in all other methods."