function?[?alpha?alpham?nalpham?alphac?]?=?alpharec（?A?B?Pi?）
%?alpharec?This?function?returns?the?alpha?matrix?for?an?HMM
%
%???The?following?parameters?are?used?for?annotation
%???N????:?Numer?of?states?in?HMM
%???T????:?Number?of?observations?（in?the?HW?it?is?written?Mw）
%???Q????:?States?in?the?HMM
%???x????:?observations?in?the?HMM
%???x（i）?:?the?observation?for?frame/time?i
%???j????:?current?state
%???i????:?previous?state
%
%???The?following?parameters?are?passed?to?the?function
%???A?:?NxN?transition?matrix?describing?the?pobality?that?the?next
%???????state?is?Q（j）?given?that?the?previous?state?is?Q（i）?or?a（ij）.
%???B?:?NxT?Observation?probability?matrix?describing?the?probaility?that?
%???????we?get?observation?x（t）?given?that?the?current?state?is?Q（j）
%???Pi:?1xN?initial?probability?matrix.??This?matrix?is?non?negative?and
%???????sums?to?1.??It?gives?the?probability?that?we?start?in?Pi（n）.
%
%???The?following?paramters?are?returned?by?the?function
%???alpham?:?a?NxT?matrix?representing?the?alpha?value?given?（jt）
%????????????which?is?the?proposed?state?and?the?current?time/frame
%???alpha??:?a?scalar?that?represents?the?summation?of?all?values
%??????????:?in?alpham?for?the?HMM

%???First?we?initialize?the?first?column?of?alpha?with:
%??????alpham（1j）?=?p（j）*p（x（1）|j）
%???The?we?recursively?move?forward?across?the?matrix?with:
%??????alpham（tj）?=?p（x（t）|j）*sum（alpha（i）*p（j|i）?from?i=1:N）???

t?=?1;?%?the?current?frame/time
j?=?1;?%?the?current?state
[N?T]?=?size（B）;?%?the?number?of?states?and?observations?in?the?HMM
alpham?=?zeros（N?T）;
nalpham?=?zeros（N?T）;

%?to?avoid?underflow?the?alpha?matrix?values?are?all?normalized?to?1
%?these?normalization?factors?are?also?passed?to?the?beta?matrices
alphac?=?zeros（1?T）;

%?code?adapted?from?http://www.shokhirev.com/nikolai/abc/alg/hmm/HMM_cpp.html

%?initialize?the?first?column?of?the?alpha?vector;
for?j?=?1:N
???alpham（j?t）?=?Pi（j）*B（jt）;
???nalpham（j?t）?=?Pi（j）*B（jt）;
???alphac（1?t）?=?alphac（1?t）?+?alpham（j?t）;
end
for?j?=?1:N
????alpham（j?t）?=?alpham（jt）/alphac（1t）;
end
%?recursively?move?forward?across?the?matrix
for?t?=?1:T-1
????for?j?=?1:N
????????sum1?=?0;
????????sum2?=?0;
????????for?i?=?1:N
????????????sum1?=?sum1+alpham（it）*A（ij）;
????????????sum2?=?sum2?+?nalpham（it）*A（ij）;
????????end
????????alpham（jt+1）?=?sum1*B（jt+1）;
????????nalpham（jt+1）?=?sum2*B（jt+1）;
????????alphac（1?t+1）?=?alphac（1?t+1）?+?alpham（j?t+1）;
????end
????%?apply?scalar?values?to?each?state?at?time?t
????for?j?=?1:N
????????alpham（j?t+1）?=?alpham（jt+1）/alphac（1t+1）;
????end
end

%?termination
%?t?=?T;
%?alpha?=?0;
%?for?j?=?1:N
%?????alpha?=?alpha?+?alpham（jt）;
%?end
%?for?the?scaled?vector?we?can?now?use?the?product?of?the?scalars
%?to?find?our?total?probability?of?obesrving?the?given?events
alpha?=?sum（log（alphac））;

end

?屬性????????????大小?????日期????時間???名稱
-----------?---------??----------?-----??----
?????目錄???????????0??2015-08-26?00:37??MySpeechRecognition-master\
?????文件???????64044??2015-08-26?00:37??MySpeechRecognition-master\?test.wav
?????文件?????????302??2015-08-26?00:37??MySpeechRecognition-master\.gitignore
?????目錄???????????0??2015-08-26?00:37??MySpeechRecognition-master\Matlab\
?????文件???????11264??2015-08-26?00:37??MySpeechRecognition-master\Matlab\EMTraining.m
?????文件????????1328??2015-08-26?00:37??MySpeechRecognition-master\Matlab\HMMgammaposteri.m
?????文件?????????598??2015-08-26?00:37??MySpeechRecognition-master\Matlab\HMMtest.m
?????文件????????1781??2015-08-26?00:37??MySpeechRecognition-master\Matlab\HMMxiposteri.m
?????文件????????1099??2015-08-26?00:37??MySpeechRecognition-master\Matlab\Homework4.m
?????文件?????????830??2015-08-26?00:37??MySpeechRecognition-master\Matlab\UpdatePi.m
?????文件????????2852??2015-08-26?00:37??MySpeechRecognition-master\Matlab\alpharec.m
?????文件????????2370??2015-08-26?00:37??MySpeechRecognition-master\Matlab\betarec.m
?????文件?????????860??2015-08-26?00:37??MySpeechRecognition-master\Matlab\filterbankmulttest.m
?????文件???????16522??2015-08-26?00:37??MySpeechRecognition-master\Matlab\four.wav
?????文件???????18040??2015-08-26?00:37??MySpeechRecognition-master\Matlab\four10.wav
?????文件???????17036??2015-08-26?00:37??MySpeechRecognition-master\Matlab\four2.wav
?????文件???????16410??2015-08-26?00:37??MySpeechRecognition-master\Matlab\four3.wav
?????文件???????17514??2015-08-26?00:37??MySpeechRecognition-master\Matlab\four4.wav
?????文件???????17102??2015-08-26?00:37??MySpeechRecognition-master\Matlab\four5.wav
?????文件???????17156??2015-08-26?00:37??MySpeechRecognition-master\Matlab\four6.wav
?????文件???????17670??2015-08-26?00:37??MySpeechRecognition-master\Matlab\four7.wav
?????文件???????17586??2015-08-26?00:37??MySpeechRecognition-master\Matlab\four8.wav
?????文件???????17742??2015-08-26?00:37??MySpeechRecognition-master\Matlab\four9.wav
?????文件????????3003??2015-08-26?00:37??MySpeechRecognition-master\Matlab\fourlambda.mat
?????文件?????????876??2015-08-26?00:37??MySpeechRecognition-master\Matlab\gMeanAndVar.m
?????文件????????1501??2015-08-26?00:37??MySpeechRecognition-master\Matlab\melfilterbank.m
?????文件????????1240??2015-08-26?00:37??MySpeechRecognition-master\Matlab\melfrequencies.m
?????文件????????3171??2015-08-26?00:37??MySpeechRecognition-master\Matlab\my_mfcc.m
?????文件???????11746??2015-08-26?00:37??MySpeechRecognition-master\Matlab\one.wav
?????文件???????12214??2015-08-26?00:37??MySpeechRecognition-master\Matlab\one10.wav
?????文件???????12726??2015-08-26?00:37??MySpeechRecognition-master\Matlab\one2.wav
............此處省略44個文件信息