Question about Plot[] algorythm.
- To: mathgroup at smc.vnet.net
- Subject: [mg107554] Question about Plot[] algorythm.
- From: Alexey <lehin.p at gmail.com>
- Date: Wed, 17 Feb 2010 07:01:03 -0500 (EST)
Hello,
I am wondering that sometimes Plot[] takes a huge number of points
where a function changes very slowly. And it takes less points where
the function changes rapidly! Consider the following:
cache = {};
f[x_?NumericQ] := (AppendTo[cache, x]; 5 Csc[x]);
pl = Plot[f[x], {x, 0, 2}, PlotRange -> {Full, {0, 140}}];
Show[Histogram[cache], pl, PlotRange -> {All, {0, 140}}]
cache // Length
It is easy to see that Plot takes 122 points around x=1.5 - where the
function is nearly constant! But around x=0.3 (where the function
changes rapidly) it takes only 50 points!
Can anyone explain this?
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- Re: Question about Plot[] algorythm.
- From: Murray Eisenberg <murray@math.umass.edu>
- Re: Question about Plot[] algorythm.