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RE: Re: scaled complementary error function in Mathematica?

• To: mathgroup at smc.vnet.net
• Subject: [mg69275] RE: [mg69259] Re: scaled complementary error function in Mathematica?
• From: "Erickson Paul-CPTP18" <Paul.Erickson at Motorola.com>
• Date: Tue, 5 Sep 2006 05:30:38 -0400 (EDT)
• Sender: owner-wri-mathgroup at wolfram.com

It would seem that by the time Exp[x^2]*Erfc[x] runs into exponent
trouble, that the approximation 1/(x Sqrt[Pi]) would be sufficiently
accurate for most numeric calculations. Thus, you might form a function
like

scaledErfc[ x_ ] := If[ x < 25000, Exp[x^2]*Erfc[x] , 1/(x Sqrt[Pi]) ]

-----Original Message-----
From: Peter Pein [mailto:petsie at dordos.net] 
To: mathgroup at smc.vnet.net
Subject: [mg69275] [mg69259] Re: scaled complementary error function in
Mathematica?

Tanim Islam schrieb:
> Hi:
> 
> I was wondering if anyone had a package or notebook file that computes

> the scaled complementary error function directly? Specifically, 
> something that computes exp(x^2) erfc(x)? Thanks a bunch.
> 
> Tanim Islam

Hello,

what is wrong with Exp[x^2]*Erfc[x]?

Peter