From chyihung.hsu@pharma.Novartis.com  Mon Mar 19 21:52:04 2001
From: chyihung.hsu@pharma.Novartis.com (chyihung.hsu@pharma.Novartis.com)
Date: Mon, 19 Mar 2001 22:52:04 +0100 (MET)
Subject: [Rd] A limitation for polyroot ? (PR#880)
Message-ID: <200103192152.WAA19583@pubhealth.ku.dk>

Dear R Development Team,

I have encountered the following difficulty in using the function polyroot
under either NT4.0  (R version 1.2.1) or linux (R version 0.90.1).  In the
provided example, the non-zero root of c(0,0,0,1) depends on the results of
the previous call of polyroot.

R : Copyright 2001, The R Development Core Team
Version 1.2.1  (2001-01-15)

R is free software and comes with ABSOLUTELY NO WARRANTY.
You are welcome to redistribute it under certain conditions.
Type `license()' or `licence()' for distribution details.

R is a collaborative project with many contributors.
Type `contributors()' for more information.

Type `demo()' for some demos, `help()' for on-line help, or
`help.start()' for a HTML browser interface to help.
Type `q()' to quit R.

[Previously saved workspace restored]

> polyroot(c(6,-5,1))
[1] 2+1.615587e-27i 3-1.615587e-27i
> polyroot(c(0,0,0,1))
[1] 0+0.000000e+00i 0+0.000000e+00i 3-1.615587e-27i
> polyroot(c(4,-4,1))
[1] 2+1.110223e-16i 2-1.110223e-16i
> polyroot(c(0,0,0,1))
[1] 0+0.000000e+00i 0+0.000000e+00i 2-1.110223e-16i
>

Thank you for your attention.

Best regards,

Chyi-Hung Hsu


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[Rd] A limitation for polyroot ? (PR#880)
chyihung.hsu@pharma.Novartis.com