Re: [boost] RTL

From: Calum Grant (calum_at_[hidden])
Date: 2005-10-18 14:52:19

> > The problem with this data is that it contains a lot of 
> duplicates.  
> > If I cluster the cities into 5103 clusters, I get 47ms.  On 
> the other 
> > hand if I don't cluster them, then I get 4.1s.  The 
> expensive part is 
> > building the index of indexing on distances.  The results 
> are rather 
> > odd
> > - the 500 locations I get have 991 neighbours.
> 
> This sounds like a correct result -- can I see the first 50 items?

The output is at the bottom.

I've managed to get my times down a bit by reimplementing the solution
in a much more straightforward way.  I can insert all 21421 items,
calculate the number of neighbours, and display the top 500 in 235ms.
Then I can remove 1982 items, and redisplay the results, in 47
milliseconds.  This of course makes me suspicious that I'm doing
something wrong.........

The solution I have is not terribly elegant from RML's point of view,
since as I said before RML is designed for logical queries rather than
numerical computation.  It was not a terribly interesting problem
because it needed just a single table with two indexes.

Regards, 

Calum

===============================================
     17882                      ALTEC-AS       991
     16918                      BILIM-AS       991
     16917               IXEUROPE-FR-ASN       991
      8734                   WISH-NOKNOK       991
     16915                      DHMS-NET       991
     17700                     IOMART-AS       991
     17494                     RAMSATCOM       991
     17670                         GETIT       991
     17493                      AS-IKSYS       991
     16913                   UNSPECIFIED       991
     16912                      ASN-MPLS       991
     17491                           ABB       991
     17490                   UNSPECIFIED       991
     17698               MEGAPROVIDER-AS       991
     18013                      CITCO-AS       991
     16911                     YACAST-AS       991
     17803                         KHODA       991
....
     17278                  AS-PETERSTAR       991
      6399                      Novaxess       991
     17277                   UNSPECIFIED       991
     17868                  RTK-Primorye       991
     17276                   UNSPECIFIED       991
     17275                AS-SYNCHROLINE       991
     11605                   UNSPECIFIED       991
     18167                          RIPE       991
     17274                  AS-SUNET2000       991
     11599                   Swisscom-NA       991
     11598                   HPPOLAND-AS       991
     17273                      STARTVAS       991
There are 21421 locations
     17219                   ASN-CEDECRA       990
     17587                   UNSPECIFIED       990
     17778                   KIWWI-HU-AS       990
     17777                      Actimage       990
     17433                    EBS-Europe       990
...
     17280                   LiberCom-AS       990
     18207                          RIPE       990
     18206                          RIPE       990
     17279                    UNIFFM-NET       990
     17493                      AS-IKSYS       990
There are 19439 locations
Insert time = 234 milliseconds
Delete and redisplay = 47 milliseconds