Walter Neumann on Thu, 12 May 2005 07:29:53 +0200


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Re: erfc() behavior change



On Wed, 11 May 2005, Igor Schein wrote:

Hi,

\\ ver 2.2.9
? for(k=1,10,print(k" "precision(erfc(2^k))" "precision(erfc(-2^k))))
...
10 455407 455446
\\ ver 2.2.10
? for(k=1,10,print(k" "precision(erfc(2^k))" "precision(erfc(-2^k))))
...
10 38 455446

?

Thanks

Igor


The second (2.2.10) looks better to me:

GP/PARI CALCULATOR Version 2.2.11 (development CHANGES-1.1205)

? erfc(2^10)
%1 = 9.342620665669385261706140592 E-455395
? precision(%)
%2 = 28
? erfc(-2^10)
%3 = 2.000000000000000000000000000
? precision(%)
%4 = 455427
? 2-%3
%5 = 9.342620665669385261706140592 E-455395
? precision(%)
%6 = 38
?

--walter neumann