function?[K]?=?kernel（kerxy）
%?Calculate?kernel?function.???
%
%?x:?輸入樣本d×n1的矩陣n1為樣本個(gè)數(shù)d為樣本維數(shù)
%?y:?輸入樣本d×n2的矩陣n2為樣本個(gè)數(shù)d為樣本維數(shù)
%
%?ker??核參數(shù)（結(jié)構(gòu)體變量）
%?the?following?fields:
%???type???-?linear?:??k（xy）?=?x‘*y
%????????????poly???:??k（xy）?=?（x‘*y+c）^d
%????????????gauss??:??k（xy）?=?exp（-0.5*（norm（x-y）/s）^2）
%????????????tanh???:??k（xy）?=?tanh（g*x‘*y+c）
%???degree?-?Degree?d?of?polynomial?kernel?（positive?scalar）.
%???offset?-?Offset?c?of?polynomial?and?tanh?kernel?（scalar?negative?for?tanh）.
%???width??-?Width?s?of?Gauss?kernel?（positive?scalar）.
%???gamma??-?Slope?g?of?the?tanh?kernel?（positive?scalar）.
%
%?ker?=?struct（‘type‘‘linear‘）;
%?ker?=?struct（‘type‘‘ploy‘‘degree‘d‘offset‘c）;
%?ker?=?struct（‘type‘‘gauss‘‘width‘s）;
%?ker?=?struct（‘type‘‘tanh‘‘gamma‘g‘offset‘c）;
%
%?K:?輸出核參數(shù)n1×n2的矩陣

%-------------------------------------------------------------%

switch?ker.type
????case?‘linear‘
????????K?=?x‘*y;
????case?‘ploy‘
????????d?=?ker.degree;
????????c?=?ker.offset;
????????K?=?（x‘*y+c）.^d;
????case?‘gauss‘
????????
????????s?=?ker.width;
????????rows?=?size（x2）;
????????cols?=?size（y2）;???
????????tmp?=?zeros（rowscols）;
????????for?i?=?1:rows
????????????for?j?=?1:cols
????????????????tmp（ij）?=?norm（x（:i）-y（:j））;
????????????end
????????end????????
????????K?=?exp（-0.5*（tmp/s）.^2）;

????case?‘tanh‘
????????g?=?ker.gamma;
????????c?=?ker.offset;
????????K?=?tanh（g*x‘*y+c）;
????otherwise
????????K?=?0;
end

?屬性????????????大小?????日期????時(shí)間???名稱
-----------?---------??----------?-----??----

?????文件???????1510??2007-07-02?13:49??kernel.m

-----------?---------??----------?-----??----

?????????????????1510????????????????????1