What norm StepTolerance uses for multivariable?

7 次查看（过去 30 天）

Marcus 2024-7-18

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/2138526-what-norm-steptolerance-uses-for-multivariable

编辑： Torsten 2024-7-18

I want to define a StepTolerance for the lsqnonlin with 'trust-region-reflective'algorithm to solve a system of 4 variables, so X has dimension 4x1.

The documention Tolerance Details says that this algorithm uses a Absolute Step Tolerance.

In Tolerances and Stopping Criteria I found this:

"StepTolerance is a lower bound on the size of a step, meaning the norm of (xi – xi+1). If the solver attempts to take a step that is smaller than StepTolerance, the iterations end."

Is this norm the same of function norm, the Euclidean norm?

3 个评论
显示 1更早的评论隐藏 1更早的评论

Marcus 2024-7-18

Hi Torsten,

I'm trying to compare the lsqnonlin solver with a home made algorithm.

So, using the same stop criteria is important.

Torsten 2024-7-18

编辑：Torsten 2024-7-18

In this case, to get full control, you'd stop the iteration on your own by using the OutputFnc function. Here, you can save the convergence history of the solver and thus compare the most recent iterate x_i+1 with the previous ones x_j for j <= i during the computational process.

请先登录，再进行评论。

请先登录，再回答此问题。