Re: Time for an integration
- To: mathgroup at smc.vnet.net
- Subject: [mg100920] Re: Time for an integration
- From: David Bailey <dave at removedbailey.co.uk>
- Date: Thu, 18 Jun 2009 04:53:28 -0400 (EDT)
- References: <h19i35$p1a$1@smc.vnet.net>
Lena wrote:
> Hello !
>
> I have an integral to perform 4096 times: it is a 3dimensionnal integral over a matrix of 4096.4096 points.
>
> It takes many hours and I still does not have the result. I made a loop with NIntegrate.
>
> Is it possible that an integration loop in mathematica takes so long ? Is there any ways to improve it ?
>
> Thank you
>
> Lena
>
Well you are attempting 16 million numerical integrations, which is not
trivial!
A good start might be to add the line:
PrintTemporary[{i,j}];
to your loop, where i and j are your loop variables. This will give you
a better idea of how fast it is working, and how long it might take.
David Bailey
http://www.dbaileyconsultancy.co.uk