清空筛选条件
清空筛选条件

fminsearch with if statement

1 次查看（过去 30 天）
Christina
Christina 2013-7-26
Hello all,
I need to optimise two parameters by minimising by objective function.
I've got an equation that has got two parts.
The parameters that I want to optimise are p0 and b0.
I already got the vectors obs and p.
The equation is:
If p < p0, then sim = p +b0*p0
if p>= p0, then sim = 5
Then I need to put my simulated values into my objective function, that looks like:
OF = (sim - obs)^2
So, now I want to minimise OF using fminsearch.
How can I do that, if the parameter that I am looking for is inside the constraint?
Thanks

请先登录，再回答此问题。

采纳的回答

Matt J
Matt J 2013-7-26
[xmin, fmin] = fminsearch(@(x) OF(x,obs,p), xguess);
function val=OF(x,obs,p)
p0=x(1);
b0=x(2);
sim= (p +b0*p0).*(p<p0)+5.*(p>p0);
val=(sim - obs).^2;
  2 个评论
Christina
Christina 2013-7-27
Hey Matt!
Thanks a lot for you reply, yes, that's mainly what I'd want to do.
However, the function option does not work for me, could you suggest how this could be written, without a function, i.e. as a simple script?
Thanks a lot.
Christina
Christina 2013-7-27
Actually, I just found it.
Thanks a lot for your help!

请先登录，再进行评论。

更多回答（1 个）

Matt J
Matt J 2013-7-26
编辑：Matt J 2013-7-26
Looks like you're doing a first order spline fit with a single free knot, and therefore this FEX file might already do everything you need,
http://www.mathworks.com/matlabcentral/fileexchange/25872-free-knot-spline-approximation

类别

在 Help Center 和 File Exchange 中查找有关 Get Started with Optimization Toolbox 的更多信息

标签

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by