[Rd] A limitation for polyroot ? (PR#880)

chyihung.hsu@pharma.Novartis.com chyihung.hsu@pharma.Novartis.com
Mon, 19 Mar 2001 22:52:04 +0100 (MET)

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.

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Version 1.2.1  (2001-01-15)

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[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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