Mathematica LogPlot Bug
- To: mathgroup at smc.vnet.net
- Subject: [mg123707] Mathematica LogPlot Bug
- From: AntonioP <ant.piniz at gmail.com>
- Date: Fri, 16 Dec 2011 05:47:08 -0500 (EST)
- Delivered-to: l-mathgroup@mail-archive0.wolfram.com
Hello,
I have to draw some functions in log scale, but LogPlot seems not to
be able to draw them correctly if the y-value is too small.
A simple case:
f[x_] = 10^(-5 x)
LogPlot[f[x], {x, 1, 100}, PlotRange -> Full]
the plot should be a simple straight line for any x value,
while at about x=61.5 there is a step and, for any greater value of x,
the function appears to be constant.
Nevertheless, Mathematica is able to compute the correct value of f[x]
for any x:
N[f[60]]
N[f[65]]
N[f[80]]
N[f[100]]
There is a similar problem for large y-values, as well.
Apparently there is a y-range, about (10^-308, 10^308), outside which
LogPlot doesn't work correctly.
Any idea on how to resolve the problem?
Thanks,
Antonio