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Re: machine precision number plot fixed in V6?

• To: mathgroup at smc.vnet.net
• Subject: [mg83076] Re: machine precision number plot fixed in V6?
• From: "David Park" <djmpark at comcast.net>
• Date: Fri, 9 Nov 2007 05:21:07 -0500 (EST)
• References: <fgurjm$rh4$1@smc.vnet.net>

In Version 6 you can specify a WorkingPrecision option in graphics 
statements. I believe that this replaces the need for Ted's PrecisionPlot 
package (which might still be needed for pre Version 6.)


-- 
David Park
djmpark at comcast.net
http://home.comcast.net/~djmpark/


<congruentialuminaire at yahoo.com> wrote in message 
news:fgurjm$rh4$1 at smc.vnet.net...
> 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
>
>