What is the logic behind fzero and fsolve which make fsolve's speed faster than fzero?

Question

Yong Siew Kuan 2016-10-12

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/306951-what-is-the-logic-behind-fzero-and-fsolve-which-make-fsolve-s-speed-faster-than-fzero

评论： Dariusz Skibicki 2021-3-23

What is the logic behind fzero and fsolve which make fsolve's speed faster than fzero? Suppose that there is a polynomial equation, it can be solved by root function in shortest time, following by fsolve and fzero. Why is it so?

0 个评论
显示 -2更早的评论隐藏 -2更早的评论

请先登录，再进行评论。

请先登录，再回答此问题。

Answer 1

Massimo Zanetti 2016-10-12

6
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/306951-what-is-the-logic-behind-fzero-and-fsolve-which-make-fsolve-s-speed-faster-than-fzero#answer_238662

编辑：Massimo Zanetti 2016-10-12

The functions fsolve and fzero are not meant to solve the same problem. Specifically:

fzero: It finds the root of a function (of one variable) in an interval [a,b]. It REQUIRES that f(a)*f(b)<0. fzeros uses a combination of bisection, secant, and inverse quadratic interpolation methods. Not every polynomial can be rooted by fzero: for instance x^2 doesn't work, because it has no sign change.
fsolve: solves a SYSTEM of non-linear equations F(x) where x is multivariate. It use three different methods 'trust-region-dogleg' (default), 'trust-region', and 'levenberg-marquardt', depending on user needs.