Re: BinCounts

*To*: mathgroup at smc.vnet.net*Subject*: [mg60931] Re: [mg60918] BinCounts*From*: "Carl K. Woll" <carl at woll2woll.com>*Date*: Tue, 4 Oct 2005 01:24:58 -0400 (EDT)*References*: <200510030806.EAA00260@smc.vnet.net>*Sender*: owner-wri-mathgroup at wolfram.com

Alberto Verga wrote: > Why does BinCounts[] give lists with unpredictable Dimensions[]? > > With[{n = 205}, ll = RandomArray[NormalDistribution[0, 1], {n}]; > Dimensions[BinCounts[ll, {Min[ll], Max[ll], (Max[ll] - Min[ll])/n}]]] > > > > You may try different values of n (or the same n and different samples of > the random numbers), and verify that the lenght of the list depends on the > random realization: somtimes you get n, somtimes n+1. > You get different results because of numerical error associated with using inexact numbers like machine numbers. Instead, use exact arithmetic or add a fudge factor. Assuming you want to get n bins, the following approach will always do so for reasonable data: BinCounts[ll, {Min[ll],Max[ll],(Max[ll]-Min[ll])/n + $MachineEpsilon}] Alternatively, you could use Rationalize by replacing Min[ll] (and Max[ll]) with Rationalize[Min[ll],0] etc. > Alberto Verga > > > Alberto Verga > > IRPHE - Université de Provence > > 49, rue F. Joliot-Curie, BP 146, > > 13384 Marseille, France > > > > Carl Woll Wolfram Research

**References**:**BinCounts***From:*Alberto Verga <Alberto.Verga@laposte.net>