Review 'default' retrieval algorithm

[renekrie]

Chorus let's the user choose from a list of pre-configured search algorithms that each yield different result sets and rankings.

The default algorithm is a pretty bad one that we would always de-recommend in e-commerce search, eg. using mm<100%. This is problematic from a number of perspectives:

• As Chorus is meant to be an example application for a good e-commerce search, the default algorithm should be a reasonably good one
• As we are adding vector search, we default increasingly serves as a reference for comparison, which would not make sense, if it is so bad that nobody would use it in practice. More concretely, we have a search algorithm that uses vectors for boosting but keywords for retrieval. Which algorithm would we compare it to? Should we turn on mm=100% for hybrid search? - In the context of telling the story - default vs. hybrid search - we should keep it off. But in a more general e-commerce search context, it doesn't make sense.