Hi, you can use http://www.codeproject.com/KB/recipes/zigurat.aspx example or read the BOOST manual on accumulators. typedef accumulator_set<double, stats<boost::accumulators::tag::tail_quantile<left> > > accumulator_t_left; typedef accumulator_set<double, stats<boost::accumulators::tag::tail_quantile<right> > > accumulator_t_right; accumulator_t_right acc0( boost::accumulators::tag::tail<right>::cache_size = c ); { // here push your data in to acc0 acc0(r); } get the quantile or whatever: double tqueryP=quantile(acc0, quantile_probability = 0.50 ); cheers Arman. On Wed, Apr 28, 2010 at 3:54 PM, David Doria <daviddoria@gmail.com> wrote:

On Tue, Apr 27, 2010 at 4:19 PM, David Doria <daviddoria@gmail.com> wrote:

...

Does boost have a way to make a histogram of a vector?

I want to be able to do queries such as:

"Which numbers are in the 90th percentile?"

Thanks,

David

Maybe a better explanation is I want a c++ function that will do what the Matlab hist() function does: http://www.mathworks.com/access/helpdesk/help/techdoc/ref/hist.html

Thanks,

David _______________________________________________ Boost-users mailing list Boost-users@lists.boost.org http://lists.boost.org/mailman/listinfo.cgi/boost-users

-- ------------------------------------------ Dr Arman Khalatyan, Observatoire Astronomique de Marseille-Provence Laboratoire d'Astrophysique de Marseille -----------------------------------------

Thanks Paul, I'll check it out. Arman helped me get to a working demo (below) but I am still a bit confused. 1) What is the "cache"/"cache size"? 2) Does this line: double tqueryP = quantile(acc0, quantile_probability = 0.50 ); tell you the percentage of the input values that fall in the top 50% of all input values? Here is the code: std::vector<double> data(100); std::generate(data.begin(), data.end(), data_filler<double>()); int c = data.size();//cache size for histogramm. //create a accumulator. accumulator_t_right acc0( boost::accumulators::tag::tail<right>::cache_size = c ); //fill accumulator for (int j = 0; j < c; ++j) { acc0(data[j]); } //ask some questions... double tqueryP = quantile(acc0, quantile_probability = 0.50 ); std::cout << tqueryP << std::endl; Also, with this code: 1) again, what is the cache_size? 2) Is there a way to get a list of the values that are in each bin? Or only the percentage of the input values that fall in the bin? //create some random data std::vector<double> data(100); std::generate(data.begin(), data.end(), data_filler<double>()); int c = data.size();//cache size for histogramm. //create a accumulator. acc myAccumulator( tag::density::num_bins = 20, tag::density::cache_size = 10); //fill accumulator for (int j = 0; j < c; ++j) { myAccumulator(data[j]); } //ask some questions... //double query = density(myAccumulator); histogram_type hist = density(myAccumulator); double total = 0.0; for( int i = 0; i < hist.size(); i++ ) { std::cout << "Bin lower bound: " << hist[i].first << ", Value: " << hist[i].second << std::endl; total += hist[i].second; } std::cout << "Total: " << total << std::endl; //should be 1 (and it is) Thanks! David

From: boost-users-bounces@lists.boost.org [mailto:boost-users-bounces@lists.boost.org] On Behalf Of Arman Khalatyan Sent: Thursday, April 29, 2010 10:58 AM To: boost-users@lists.boost.org Subject: Re: [Boost-users] Histogram

Paul,thanks for reminding SVG stl library, I did not knew that IE does not support SVG:) 

But with the Adobe addin (still widely available for download but not from Adobe), it does – and IE9 promises full support at last (which means I might resume work on this). (And you can also easily use Inkscape to convert to png if you prefer that).

are there plans to add Latex formatting for the Greek/Math symbols for titles and axises? that will be useful feature,at least for me:)

You can already even more easily do this (at least for single line labels) using Unicode – there are several examples of this in the sandbox. Finally sub and subscript support for Mozilla Firefox is promised soon. This is a must-have for units labels of course. Paul --- Paul A. Bristow Prizet Farmhouse Kendal, UK LA8 8AB +44 1539 561830, mobile +44 7714330204 pbristow@hetp.u-net.com