[Openspace] Memory Problems

[Julia Koschinsky]

Yes, we've encountered the same problem before for large 
datasets with k-nearest neighbor distance weights and x-y 
coordinates that are in very close proximity.

If you cannot get it to run in GeoDa, you could try running 
an instrumental variables model, e.g., in R, which is free 
as well.

Julia

---- Original message ----
>Date: Fri, 16 Sep 2005 19:04:09 +0000
>From: "David Barker" <barkrich at msn.com>  
>Subject: Re: [Openspace] Memory Problems  
>To: koschins at uiuc.edu, openspace at sal.uiuc.edu
>
>Thank you for the reply.  I was using a distance weights 
matrix.  If I use a 
>very short distance threshold it works, but I would like to 
use a longer 
>threshold.
>
>The data are latitude and longitude points, pooled time 
series cross 
>section.
>
>
>>From: Julia Koschinsky <koschins at uiuc.edu>
>>Reply-To: koschins at uiuc.edu
>>To: David Barker <barkrich at msn.com>, openspace at sal.uiuc.edu
>>Subject: Re: [Openspace] Memory Problems
>>Date: Fri, 16 Sep 2005 13:51:13 -0500
>>
>>David,
>>
>>What kind of weights matrix are you using? The run time is
>>not only dependent on your sample size but also on the
>>complexity of your neighborhood structure. We've run 
spatial
>>regressions in GeoDa for about 100,000 in 20 minutes with
>>rook for some datasets and had to wait much longer or
>>switched to instrumental variables estimation for others.
>>
>>Did you try running the regression with a different weights
>>matrix (e.g., rook, if you have a polygon file) to test 
this?
>>
>>Julia
>>
>>---- Original message ----
>> >Date: Fri, 16 Sep 2005 16:58:51 +0000
>> >From: "David Barker" <barkrich at msn.com>
>> >Subject: [Openspace] Memory Problems
>> >To: openspace at sal.uiuc.edu
>> >
>> >I get an ?Out of Memory? error when running a spatial 
error
>>regression with
>> >a large number of observations (around 30,000).  Adding
>>more virtual memory
>> >seemed to help ? it took longer for the error to pop up,
>>but there are
>> >limits to the amount of virtual memory I can use in
>>Windows  2000.  If I
>> >switch to the new 64 bit version of Windows (Windows XP
>>Professional x64)
>> >will that help?
>> >
>> >
>> >
>> >I was able to create the weights matrix, although it 
took a
>>while!
>> >
>> >
>> >_______________________________________________
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>> >Openspace at sal.uiuc.edu
>> >http://sal.uiuc.edu/mailman/listinfo/openspace
>
>