Q: dynamic playlist of unrated songs

[Leo Franchi]

On Jun 28, 2009, at 9:13 PM, D. R. Evans wrote:

> Leo Franchi said the following at 06/28/2009 07:01 PM :
>
>>>
>>> Suppose I want to populate a playlist with random songs from the set
>>> { unrated } ∪ { 5 stars }
>>> How would I do that?
>>>
>>> The closest I have been able to come seems to select with equal
>>> probability
>>> from the two sets { unrated } and { 5 stars }, which isn't the same
>>> thing
>>> at all :-(
>>
>> If you set two 100% proportional biases, you'll end up with a  
>> randomly
>> selected playlist that always picks from one of those two possible
>> conditions.
>
> Right; that's exactly what I did, with the results I described :-(
>
> Selecting with equal probability from two disjoint sets is not (in  
> general)
> at all the same as selecting randomly from the union of those sets (an
> operation which was trivial in 1.4, and which is what I'm trying to  
> do).

Ah, I see now. Unfortunately, due to the design of the system (non- 
optimal, I would say), the way multiple Biases are stacked together  
doesn't allow us to select over the union of the matching tracks.  
Rather, each bias is computed independently.

cheers,
leo