machine precision number plot fixed in V6?
- To: mathgroup at smc.vnet.net
- Subject: [mg83064] machine precision number plot fixed in V6?
- From: congruentialuminaire at yahoo.com
- Date: Fri, 9 Nov 2007 05:14:52 -0500 (EST)
Hello Mathematica UG:
I was doing some work with the PrecisionPlot package (http://
library.wolfram.com/infocenter/MathSource/715/)
When I ran it under V6, no output was emitted. So I looked again at
the documentation provided by Ted Ersek. Even though it is 8 years
old, it contains the following function and plot which does not work
correctly as recently as V5.
In V6, the invocation with SetPrecision works and emits a smooth plot
(presumably eliminating the need for this package). Here are the lines
of code.
-----------------------------------------------------------
(* a function that does not plot well with machine-precision numbers
*)
f2[x_] = ArcSec[x] - Normal[Series[TrigToExp[ArcSec[x]], {x, \
[Infinity], 7}]]
(* a jagged plot results under V5 and V6 *)
Plot[f2[t], {t, 25, 40}]
(* a smooth plot results only under V6 *)
Plot[f2[SetPrecision[t, 17]], {t, 25, 40}]
------------------------------------------------------------
If there is a simple explanation for what was fixed in V6 to make this
work, I am interested to know.
TIA.
Regards..Roger