function?[test_targets?E]?=?ada_boost（train_patterns?train_targets?test_patterns?params）

%?Classify?using?the?AdaBoost?algorithm
%?Inputs:
%?	train_patterns	-?Train?patterns
%	train_targets	-?Train?targets
%???test_patterns???-?Test??patterns
%	Params	-?[NumberOfIterations?Weak?Learner?Type?Learner‘s?parameters]
%
%?Outputs
%	test_targets	-?Predicted?targets
%???E???????????????-?Errors?through?the?iterations
%
%?NOTE:?Suitable?for?only?two?classes
%

[k_max?weak_learner?alg_param]?=?process_params（params）;

[NiM]			=?size（train_patterns）;
W			?	=?ones（1M）/M;
IterDisp		=?10;

full_patterns???=?[train_patterns?test_patterns];
test_targets????=?zeros（1?size（test_patterns2））;

%Do?the?AdaBoosting
for?k?=?1:k_max
???%Train?weak?learner?Ck?using?the?data?sampled?according?to?W:
???%...so?sample?the?data?according?to?W
???randnum?=?rand（1M）;
???cW	???=?cumsum（W）;
???indices?=?zeros（1M）;
???for?i?=?1:M
??????%Find?which?bin?the?random?number?falls?into
??????loc?=?max（find（randnum（i）?>?cW））+1;
??????if?isempty（loc）
?????????indices（i）?=?1;
??????else
?????????indices（i）?=?loc;
??????end
???end
???
???%...and?now?train?the?classifier
???Ck?	=?feval（weak_learner?train_patterns（:?indices）?train_targets（indices）?full_patterns?alg_param）;

???%Ek?<-?Training?error?of?Ck?
???E（k）?=?sum（W.*（Ck（1:M）?~=?train_targets））;
???
???if?（E（k）?==?0）
??????break
???end
???
???%alpha_k?<-?1/2*ln（1-Ek）/Ek）
???alpha_k?=?0.5*log（（1-E（k））/E（k））;
???
???%W_k+1?=?W_k/Z*exp（+/-alpha）
???W??=?W.*exp（alpha_k*（xor（Ck（1:M）train_targets）*2-1））;
???W??=?W./sum（W）;
???
???%Update?the?test?targets
???test_targets??=?test_targets?+?alpha_k*（2*Ck（M+1:end）-1）;
???
???if?（k/IterDisp?==?floor（k/IterDisp））
??????disp（[‘Completed?‘?num2str（k）?‘?boosting?iterations‘]）
???end
???
end

test_targets?=?test_targets?>?0;

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

?????文件??????55045??2009-02-01?20:32??AdaBoost完整實現(xiàn)\AdaBoost.rar

?????文件???????1892??2003-06-26?20:48??AdaBoost完整實現(xiàn)\Ada_Boost.m

?????文件??????38627??2009-02-25?17:22??AdaBoost完整實現(xiàn)\MyFistProgamme2.rar

?????目錄??????????0??2009-02-27?18:58??AdaBoost完整實現(xiàn)

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

????????????????95564????????????????????4