Constantinos Loizides wrote: > > Dear Rooters, > > I am looking for an easy (and fast) way to automatically adjust the range > of the histogram's axes after I filled it with some data, of which I > don't know exactly the range in the first place. > > Obviously there is one way: Before I create the histogram, I could check > the whole data for min and max values, set the range of the histogram and > fill it - but before I do that, I want to be > sure that there is no better way. The automatic binning is implemented in Root when creating histograms from Ntuples/trees. The algorithm used is a naive algorithm storing the first few thousand entries into a buffer, then compute the min/max , fill the histogram. This technique does not work well in case of data not randomly distributed. In the Hbook package, I implemented a different technique consisting in buffering also the first entries, then doubling the bin size in case of under/overflow. This technique had also problems and was not appropriate in case of 2-d histograms. It could be implemented in Root for 1-d histograms. Rene Brun
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