Gaussian kernel scale for RBF SVM
显示 更早的评论
Hi All, I'm using RBF SVM from the classification learner app (statistics and machine learning toolbox 10.2), and I'm wondering if anyone knows how Matlab came up with the idea that the kernel scale is proportional to the sqrt(P) where P is the number of predictors. Additionally, it says "The software divides all elements of the predictor matrix X by the value of KernelScale", does this mean the kernel scale is simply 1/sigma^2? source: https://www.mathworks.com/help/stats/templatesvm.html#input_argument_namevalue_KernelScale. Thanks!
采纳的回答
Akira Agata
2017-3-9
Assuming the RBF kernel function with scaling parameter (gamma) as follows:
Then, the SVM model should be set using "KernelScale" like this.
mdlSVM = fitcsvm(..., 'KernelScale', 1/sqrt(gamma));
7 个评论
vince65201
2017-3-9
Jorge Pesantez
2018-11-3
I hope I can get an answer from this thread. How do you define gamma using fitcsvm?. I've been looking for a name-value and there is no gamma definition. Thanks
Akira Agata
2018-11-5
编辑：Akira Agata
2018-11-5
Hi Jorge-san,
In fitcsvm function, default value of gamma is 1. If you want to use other value, you should define gamma by yourself, like:
gamma = 0.8;
mdlSVM = fitcsvm(..., 'KernelScale', 1/sqrt(gamma));
Zee Idrees
2018-12-9
Can you please share the code of above equation? I need that code for my project... I need help
Akira Agata
2018-12-9
fitcsvm is one of many useful functions which the "Statistics and Machine Learning Toolbox" provides. More details and some sample code can be found in the following documentation page.
Tsalsabilla Winny Junika
2019-6-1
what about the svm classify?
更多回答（0 个）
类别
在 帮助中心 和 File Exchange 中查找有关 Discriminant Analysis 的更多信息
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!
Translated by 
