clc;clear?all;close?all;

syms?x1?x2?k;

x=[12-1-2;
???11-1-1;];
class_x=[1;1;-1;-1;];%define?a?matrix?to?sign?the?class?of?samples
N=length（x）;

k0_x=0;%initialize?the?K?and?the?m
m=zeros（4100）;

j=1;
k=k0_x+class_x（1）*exp（-（（x1-x（11））^2+（x2-x（21））^2））;

j=j+1;
counter=j;%define?counter?to?memorize?the?number?of?steps
a_j=zeros（1001）;

while?j<=N
????%judge?and?decide?the?value?of?a_j????
????if?（class_x（j）==1&&subs（k[x1x2][x（1j）x（2j）]）>0）||（class_x（j）==-1&&subs（k[x1x2][x（1j）x（2j）]）<0）
????????a_j（counter）=0;
????end
????if?class_x（j）==1&&subs（k[x1x2][x（1j）x（2j）]）<=0
????????a_j（counter）=1;
????end
????if?class_x（j）==-1&&subs（k[x1x2][x（1j）x（2j）]）>=0
????????a_j（counter）=-1;
????end

????%calculate?the?new?K
????k=k+a_j（counter）*e