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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



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