|Re: Question for Tim Wessman|
Message #7 Posted by Didier Lachieze on 3 Sept 2010, 3:04 a.m.,
in response to message #6 by Namir
You may be interested by the discussion/comparison of several Polynomial Rootfinder programs as well as the matlab sample program (Appendix A) in this document: Iterative Methods for Roots of Polynomials
Regarding PROOT on HP calculators, the following post from Bill Wickes on comp.sys.hp48 back in 1992 shows that it was quite easy to port HP 71B assembler functions to the HP-48:
HP 48 Polynomial Rootfinder
Given this, I'm a bit surprised that the results for the second test on the HP 71B (+ Math Pac) and the HP 48GX (same CPU, same algorithm, same assembler code?) or the 49G+ in the following post on this forum are somewhat different (The Turtle (HP-71B) and the Hare (HP49G+) [LONG]):
0.999999999944, 1.312E-12 for the HP 71B
0.999999994032, 2.066E-12 for the 48GX
0.999999994031, 1.441E-12 for the 49G+
... the HP 71B while being the oldest machine is the closest to the exact result (1,0)!
Edited: 5 Sept 2010, 6:03 a.m.