Resolution of equation under constraints with 'fminbnd'

2 次查看（过去 30 天）

studentU 2015-6-23

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/224939-resolution-of-equation-under-constraints-with-fminbnd

评论： Walter Roberson 2015-6-26

hi, i must resolve the system of equations with two variable x and y, and i use 'solve' to do it, but i must limit the solution between an interval, can fminbnd function replace 'solve' in this case

3 个评论
显示 1更早的评论隐藏 1更早的评论

studentU 2015-6-23

编辑：studentU 2015-6-23

thank's for ue repply, YES, i have tow equations with tow unknows, and my system can have multiple solutions.

Torsten 2015-6-23

在 MATLAB Online 中打开

The reason why I ask is that it is usually not possible to restrict the solution to a certain interval.

The best you can expect is to get values for x and y such that

f1(x,y)^2+f2(x,y)^2

is minimized if you want to solve

f1(x,y)=0 and f2(x,y)=0.

If this is what you want you can proceed as Matt suggested.

Best wishes

Torsten.

请先登录，再进行评论。

请先登录，再回答此问题。

回答（1 个）

Matt J 2015-6-23

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/224939-resolution-of-equation-under-constraints-with-fminbnd#answer_183654

No, fminbnd only handles problems in a single unknown. You can use lsqnonlin, if you have the Optimization Toolbox, or you can try things on the File Exchange, like fminsearchbnd

http://www.mathworks.com/matlabcentral/fileexchange/8277-fminsearchbnd--fminsearchcon

7 个评论
显示 5更早的评论隐藏 5更早的评论

studentU 2015-6-26

it become already error: Failure in initial user-supplied objective function evaluation. LSQNONLIN cannot continue.

Walter Roberson 2015-6-26

Your x0, your initial points, is -pi/2 which is a scalar. But your objective function expects a vector of length two (or more). You need to supply a vector of length 2 instead of -pi/2

请先登录，再进行评论。

请先登录，再回答此问题。