accumulators::histogram

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.

Neal Becker wrote:
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, -- Eric Niebler Boost Consulting www.boost-consulting.com

Eric Niebler wrote:
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?

Neal Becker wrote:
I took Matthias' suggestion above to mean he thought the density accumulator could be given additional "min" and "max" constructor parameters, not that we need a whole new accumulator. Matthias, was that what you were suggesting? I'd rather go that route. -- Eric Niebler Boost Consulting www.boost-consulting.com

On Wednesday 30 January 2008, Neal Becker wrote:
Hello, It happens that I needed a similar solution. I didn't have much time and am not an expert in mpl, but I've created a rough hack from density.hpp that seems to work... And I think that this is a very useful feature, because otherwise I would have to do the hack with setting the cache to 2 and injecting 2 dummy samples with the bounds... Sending again, as during the night I sent from the wrong address and got a bounce. Milosz
participants (4)
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Eric Niebler
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Matthias Troyer
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Milosz Marian Hulboj
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Neal Becker