Weighing catalog searches per index ?
Hello, Does anybody know of a decent implementation of a scoring algorithm that does "weighing" of results, presumably based on the indexes used ? I'd like to explore the possibility of searching the catalog, but giving results from certain indexes priority over others. So in the case of the CMF, saying that if search terms are found in the Title or Descrption, they are more "important" than if they're found somewhere else and so on ... I know this is a common concept in more advanced search engines (Such as Oracle's InterMedia), but I'm wondering if anyone has done something like this in Zope ... Thanks, Jean-François Doyon Internet Service Development and Systems Support / Développement des services et soutien de systèmes Internet GeoAccess Division / Division GéoAccès Canada Center for Remote Sensing / Centre canadien de télédétection Natural Resources Canada / Ressources naturelles Canada http://atlas.gc.ca Phone: (613) 992-4902 Fax: (613) 947-2410
On Thu, 8 Jan 2004 13:43:43 -0500 Jean-Francois.Doyon@CCRS.NRCan.gc.ca wrote:
Hello,
Does anybody know of a decent implementation of a scoring algorithm that does "weighing" of results, presumably based on the indexes used ?
Low-level support for this already exists via the weightedIntersection and weightedUnion set operations. ZCatalog currently gives all indexes a weight of 1 however.
I'd like to explore the possibility of searching the catalog, but giving results from certain indexes priority over others.
It is possible to implement an index whose results are scored. This is used by TextIndexes to implement relevance ranking for instance. The index just needs to return a mapping (usually a BTree) of rid->score where rid is the record id of the catalog record. ZCatalog automatically adds these scores when intersecting results across indexes.
So in the case of the CMF, saying that if search terms are found in the Title or Descrption, they are more "important" than if they're found somewhere else and so on ...
This might be an iteresting addition to my FieldedTextIndex product. Currently all indexed fields are weighted the same, but it would be straightforward to make this configurable per field.
I know this is a common concept in more advanced search engines (Such as Oracle's InterMedia), but I'm wondering if anyone has done something like this in Zope ...
Let me know what your specific use case is and maybe I'll add it to the FieldedTextIndex product if it fits its usage. -Casey
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Casey Duncan -
Jean-Francois.Doyon＠CCRS.NRCan.gc.ca