Re: [boost] [Autosave] Re: [math][accumulators] Empirical distribution function

Subject: Re: [boost] [Autosave] Re: [math][accumulators] Empirical distribution function
From: Vadim Stadnik (vadimstdk_at_[hidden])
Date: 2011-08-11 06:36:31

Hi all,

just one comment:

 My basic concern with the code is that a map is used to store the counts of
>> data-points that have been added (the map keys are the data-points, the
>> map values are the counts). In real-world floating point data it is rare
>> for two data-points to be exactly the same, so in practice the map would
>> have a single key-value pair for each data-point q_i, of the form
>> (key=q_i,value=1). This is inefficient, because all the key values will
>> be 1. Also, the memory usage will grow linearly with the number of
>> data-points accumulated, which doesn't seem to be in keeping with the
>> spirit of the Accumulators library.
>>
>
The application looks like an analysis of data stored in a histogram. In
this case it is possible to use a map with keys of floating types. Map
provides interface parameter of predicate. This type parameter can be used
to provide equivalence of values of floating types through a tolerance
method specific to a problem domain. In theory, another possible option for
such applications is to use multimap.

Regards,
Vadim Stadnik