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Gaussian combination kernel ,Sigma1,Sigma2,Sigma3 meanings.

Member Posts: 1 Contributor I
edited November 2018 in Help

Hello

I'm trying to use SVM with Gaussian combination kernel.

However i need to enter the paramters Sigma1,Sigma2,Sigma3.

In order to pick  suitable values.Does anybody have more information about the mathmetical model and the meaning of these parameters?

Thanks

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Administrator, Moderator, Employee, RapidMiner Certified Analyst, RapidMiner Certified Expert, University Professor Posts: 3,525 RM Data Scientist

Hi Hosam,

sure Have a look at /

`com.rapidminer.operator.learner.functions.kernel.jmysvm.kernel;`

in our source code on https://github.com/rapidminer/rapidminer-studio .

The definition is:

`	public double calculate_K(int[] x_index, double[] x_att, int[] y_index, double[] y_att) {		double norm2 = norm2(x_index, x_att, y_index, y_att);		double exp1 = sigma1 == 0.0d ? 0.0d : Math.exp((-1) * norm2 / sigma1);		double exp2 = sigma2 == 0.0d ? 0.0d : Math.exp((-1) * norm2 / sigma2);		double exp3 = sigma3 == 0.0d ? 0.0d : Math.exp((-1) * norm2 / sigma3);		return exp1 + exp2 - exp3;	}`

Where norm2 is: ||x-y||^2

Best,

Martin

- Sr. Director Data Solutions, Altair RapidMiner -
Dortmund, Germany