Re: Clustering - export

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Date: Mon, 21 Jun 2004 10:35:18 -0700

You may find some answers in the FAQ at
http://groups.msn.com/AnalysisServicesDataMining
Is there any way of exporting the results that Microsoft Clustering
produces?
  Yes, but the method depends on what you mean by "results." All of the
cluster definitions are present in the content schema that you can get from
the query "SELECT * FROM <model>.CONTENT" - see the clustervieweraddin at
the site above for a sample.
  You can also get the cluster membership of cases through using the
Cluster() function (see below)

Is there any way of finding out the optimal number of clusters?
   Not directly, but you can examine the results. The problem here is how
you define the "optimal" number of clusters. There is a balance between
having enough clusters to accurately represent the data, but not so many
that you can't understand the model.

Here's a suggested approach - your cluster model should accurately cluster
holdout data. Seperate your data into two sets for training and testing.
Create many models with different cluster numbers. For each model,
determine the ClusterProbability() of each case in the test set. The model
with the highest overall cluster probability would be the optimal one, as it
best fits holdout data.

What is Cluster()?
   Cluster() is a function that returns the most likely cluster for a given
case in a prediction query. For example, using a singleton construct

SELECT Cluster() FROM MyClusterModel NATURAL PREDICTION JOIN (SELECT 'Male'
as Gender, 40 as Age) as t

Would find the most likely cluster for a 40 year-old male. The site above
has a downloadable tool for assisting in creating DMX (data mining
extension) queries

-- 
-Jamie MacLennan
SQL Server Data Mining
This posting is provided "AS IS" with no warranties, and confers no rights.
"FatherB" <FatherB@discussions.microsoft.com> wrote in message
news:84B1F7CD-26D6-46D2-8E9C-8AF6AA92922B@microsoft.com...
> Hello!
>
> I have several questions regarding clustering:
> - Is there any way of exporting the results that Microsoft Clustering
produces?
> - Is there any way of finding out the optimal number of clusters?
> - What is Cluster()?
>
> Thanks,
> Bostjan

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