From: Giovanni Mascellani Subject: Re: [PATCH 4/4] d2d1: Implement cubic bezier-line intersection. Message-Id: <68805882-3179-3665-63eb-7a0902694add@debian.org> Date: Wed, 1 Apr 2020 19:03:04 +0200 In-Reply-To: <346d7617-c4d0-2b16-35b6-e3cd92157695@gmail.com> References: <20200331201103.15219-1-conmanx360@gmail.com> <20200331201103.15219-4-conmanx360@gmail.com> <346d7617-c4d0-2b16-35b6-e3cd92157695@gmail.com> Il 01/04/20 18:46, Paul Gofman ha scritto: > Given the complex roots are not needed here and the polynomial is always > cubic, is this generic method really beneficial? It would probably be > simpler and quicker to find one root x1 with simple bisection, then > divide the polynomial into (x - x1) and deal with remaining quadratic > equation. This kind of division is typically numerically unstable. It might be that for cubic polynomials the problem is not very apparent, but given that Aberth method doesn't look that difficult to me to implement, I would go for that one. Also, I think that the Aberth method, being a variation on Newton's method, is much quicker than bisection. That said, I don't have much time to write code right now, so I won't get in the way of those who are. Just a suggestion. Giovanni. -- Giovanni Mascellani Postdoc researcher - Université Libre de Bruxelles -----BEGIN PGP SIGNATURE----- iHUEARYKAB0WIQSiBF6hBvCQNcghJEaNr8EMz954SQUCXoTJSAAKCRCNr8EMz954 SQFTAQCXvH4KUDwSugfvvazuasDlJuzcOSrTt9WgDC9zLX/yEAEA/y8Hifvp8Ap7 tpRLtX1rGUMDjv3aGUUAzIG70XRYfwM= =OXuL -----END PGP SIGNATURE-----