Re: Mathematica 6 and normal distribution?
- To: mathgroup at smc.vnet.net
- Subject: [mg77961] Re: Mathematica 6 and normal distribution?
- From: sean_incali <sean_incali at yahoo.com>
- Date: Wed, 20 Jun 2007 05:42:23 -0400 (EDT)
- References: <f532e5$33l$1@smc.vnet.net>
I got the following email from Daniel Lichtblau of Wolfram in response to my post. I figured it will be useful for everyone. > Has Mathematica 6 fixed the problems discussed in this thread? > > http://groups.google.com/group/comp.soft-sys.math.mathematica/browse_frm/thread/f3d8f7cf40057943/350a024cc20c290b?lnk=gst&q=normal+distribution&rnum=2&hl=en#350a024cc20c290b > >>From their website it seems like they are saying NormalDistribution is > new in Mathematica 6. > > Has anyone run the codes to check? Last time the problem was in the > 25th bin in the code below--with the value at 25th bin being lower > than the rest. > > SeedRandom[1111111 ]; > vec1=Table[Random[Real,{0,1000}],{10^6}]; > vec2=Map[If[#<44,1,0]&,vec1]; > ones=Flatten[Position[vec2,1]]; > plotvec=Map[Length,Split[Sort[Drop[ones-RotateRight[ones,1],1]]]]; > ListPlot[Log[plotvec],PlotRange->All] > ListPlot[plotvec,PlotRange->All] > > > Thanks for checking. > Random[] still exists for legacy purposes, and uses the same sometimes problematic generators. If you use vec1=RandomReal[{0,1000},{10^6}]; then the problem goes away in version 6. Daniel Lichtblau Wolfram Research