Re: [boost] accumulators::histogram

From: Neal Becker (ndbecker2_at_[hidden])
Date: 2008-01-30 11:26:34

Eric Niebler wrote:

> Neal Becker wrote:
>> I see accumulators::density is almost what I want.  I need a histogram,
>> but
>> it want to specify in advance the number of bins and the bin size.  This
>> is really a simplified accumulators::density.
>> 
>> I think it would be good to add this to accumulators::density.
> 
> Do these help?
> 
> tag::density::cache_size
>    Number of first samples used to determine min and max.
> 
> tag::density::num_bins
>   Number of bins (two additional bins collect under-
>   and overflow samples).
> 
> They are named parameters that you can specify to an accumulator_set's
> constructor.
> 
> accumulator_set<double, features<tag::density> > acc(
>      tag::density::cache_size = 10
>      tag::density::num_bins = 20
> );
> 
> HTH,
> 
I don't think that helps.  How can I specify apriori the number of bins and
the min and max?  AFAICT, the above would let me do this by forcing in some
fake data, that has the effect of filling the cache and thus setting
num_bins, min, max, but is has the side effect of causing that data to
effect the histogram - which is not what I need.

Unless I misunderstand, we need another (simpler) class "histogram" that
implements just this simpler behavior.  Perhaps density could be build on
top of it?