?function??bayes_classifier（feature1feature2p1p2）;
?
%-----------------------------------------------------
%?bayes_classifier（class1class2p1p2）;
%?BAYES_CLASSIFIER?function?calculates?the?discriminant?functions?for
%?two?classes.
%?INPUT?variables:
%?-?feature1?-?feature?vector?of?the?size?（m2）?for?the?first?class?（m?is?the?number?of?samples?in?the?1st?class）
%?-?feature2?-?feature?vector?of?the?size?（n2）?for?the?second?class?（n?is?the?number?of?samples?in?the?2nd?class）
%?-?p1?-?prior?probability?for?the?first?class
%?-?p2?-?prior?probability?for?the?second?class
%?OUTPUT:
%?Discriminant?functions?for?two?classes:?
%?g1（x）?=?A1*x1^2?+?B1*x1*x2?+?C1*x2^2?+?D1*x1?+?E1*x2?+?F1
%?g2（x）?=?A2*x1^2?+?B2*x1*x2?+?C2*x2^2?+?D2*x1?+?E2*x2?+?F2

%?--------------------------------------------------
%?Evgeny?Krestyannikov
%?krestyan@cs.tut.fi
%?Institute?of?Signal?Processing
%?Room?TE?313

web?-browser?http://www.ilovematlab.cn/thread-4403-1-1.html

syms?x1
syms?x2

cov1=cov（feature1）;
cov2=cov（feature2）;
mu1=mean（feature1）;
mu2=mean（feature2）;

detcov1=det（cov1）;
detcov2=det（cov2）;
invcov1=inv（cov1）;
invcov2=inv（cov2）;

W1=-0.5*invcov1;
w1=invcov1*mu1‘;

W2=-0.5*invcov2;
w2=invcov2*mu2‘;


omega1=-0.5*（mu1）*invcov1*mu1‘-0.5*log（detcov1）+log（p1）;
omega2=-0.5*（mu2）*invcov2*mu2‘-0.5*log（detcov2）+log（p2）;

omega=omega1-omega2;

X=[sym（x1）;?sym（x2）];
X_t=[sym（x1）?sym（x2）];

digits（2）;
a=X_t*（sym（W1‘d‘）*X）;
a=simplify（a）;

b=（sym（w1‘‘d‘）*X）;

c=X_t*（sym（W2‘d‘）*X）;
c=simplify（c）;

d=sym（w2‘‘d‘）*X;

eq1=a+b+sym（omega1‘d‘）;
eq2=c+d+sym（omega2‘d‘）;


disp（[‘Discriminant?function?for?the?first?class:‘]）;
disp（eq1）;
disp（[‘Discriminant?function?for?the?second?class:‘]）;
disp（eq2）;

?屬性????????????大小?????日期????時間???名稱
-----------?---------??----------?-----??----

?????文件???????1778??2008-05-28?16:34??program\bayes_classifier.m

?????文件???????1238??2008-05-28?16:35??program\data_generator.m

?????目錄??????????0??2008-05-28?16:34??program

?????文件????????122??2008-05-14?18:20??Matlab中文論壇--助努力的人完成畢業設計.url

?????文件???????3434??2008-05-15?08:26??使用幫助：新手必看.htm

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