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MathGroup Archive 2001

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Log plots: plot points *linearly* equidistant

  • To: mathgroup at smc.vnet.net
  • Subject: [mg31624] Log plots: plot points *linearly* equidistant
  • From: Primoz Peterlin <primoz.peterlin at biofiz.mf.uni-lj.si>
  • Date: Sun, 18 Nov 2001 06:29:09 -0500 (EST)
  • Sender: owner-wri-mathgroup at wolfram.com

Hello,

Browsing through the archives, I have seen this question coming up
recurringly at least since 1995, but with no satisfactory answer...

The problem is that LogLinearPlot and LogLogPlot functions evaluate plot
points at values which are *linearly* equidistant on the x-axis, not
logarithmically. Why this is erroneous can be seen on a simple example:

Needs["Graphics`Graphics`"]
LogLinearPlot[UnitStep[x - 1], {x, 0.01, 1000}]

As far as I know, there are two ways of avoiding this behaviour:

a) setting PlotDivision option to higher, often prohibitively high
values,

b) evaluating one's own list of {x,} pairs and using LogLinearListPlot
or LogLog
ListPlot to plot it

The first solution is slow and inefficient, the second one is
cumbersome. Has nobody so far been annoyed by the LogLinearPlot
behaviour enough to actually rewrite it in a decent way? :)

With kind regards,
Primoz 

-- 
Primo¾ Peterlin,   In¹titut za biofiziko, Med. fakulteta, Univerza v
Ljubljani
Lipièeva 2, SI-1000 Ljubljana, Slovenija. 
primoz.peterlin at biofiz.mf.uni-lj.si
Tel: +386-1-5437632, fax: +386-1-4315127,
http://sizif.mf.uni-lj.si/~peterlin/


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