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From Phil Steitz <p...@steitz.com>
Subject Re: [math] AbstractDescriptive Statistics
Date Sat, 29 May 2004 06:23:19 GMT
Mark R. Diggory wrote:
> 
> 
> Phil Steitz wrote:
> 
>> Mark R. Diggory wrote:
>>
>>> I'm curious about AbstractDescriptiveStatistics, currently our Type 
>>> Hierarchy looks like this:
>>>
>>> Object
>>>     --> DescriptiveStatistics (implements Statistical Summary)
>>>               --> AbstractDescriptiveStatistics
>>>                            --> DescriptiveStatisticsImpl
>>>
>>>                            --> ListUnivariateImpl
>>>                                         --> BeanListUnivariateImpl
>>>
>>>
>>> Why don't we consolidate AbstractDescriptiveStatistics into 
>>> DescriptiveStatistics? Then we will have
>>>
>>> Object
>>>     --> DescriptiveStatistics (implements StatisticalSummary)
>>>               --> DescriptiveStatisticsImpl
>>
>>
>>
>> I agree that this would be better.  The only loss is that the 
>> algorithm specification part (now in AbstractDescriptiveStatistics) 
>> would be recombined with the storage management part (now in 
>> DescriptiveStatisticsImpl).  I see no real loss in this.
>>
> 
> Now I actually understand the reason why we broke it up into two 
> classes, The Abstract class maintains the Statistics parts so they can 
> be reused in the ListUnivariateImpl etc.  Your maintaining the 
> SummaryStatistics as an abstract interface and all the Implementation is 
> in SummaryStatisticsImpl.
> 
> The modifications I'm suggesting place the methods for creating the 
> UnivariateStatistics up in DescriptiveStatistics and only the storage in 
> the Implementation. My edits basically combine DescriptiveStatistics and 
> AbstractDescriptiveStatistics (not AbstractDescriptiveStatistics and 
> DescriptiveStatisticsImpl).
> 

Viewed this way, there is no reason for SummaryStatistics to be a factory 
-- i.e., we can also collapse SummaryStatisticsImpl into 
SummaryStatistics.  I had previously been viewing the stats 
implementations as pluggable in these classes; but I am OK with this 
simplification.

Phil



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