Standard deviation and histograms

Dear Sirs,

we are currently developing a tool enabling queries based on the XML Query working draft. The tool is mainly dedicated to data analysis/mining and therefore focused on functions as count(), avg(), min()... Unfortunately we need additional functions computing "standard deviation" or "histogram" (e.g. stdv(), histogram()). The FUNCTION capability of XML Query is not an efficient way to compute these values (i.e. time consumption, lack of insert/update capabilities).

How can we manage it ? Is it possible to add these functions in the core specifications ?

Thank you in advance for you help.
Best regards

     Stéphane MBAYE 

--------------------------------------------------------------------------
     
      GAEL Consultant 
      Cité Descartes
      18, rue Albert Einstein
      77420 Champs-sur-Marne
      France 
     Software Director 
      mailto:Stephane.Mbaye@gael.fr
      http://www.gael.fr  
      tel +33-(0)1 64 73 99 55
      fax +33-(0)1 64 73 51 60