function?w?=?descent（X?y?lam）
INIT?=?100;
LIMIT?=?1e-3;
delta?=?1;
learn_rate?=?1e-12;
SIZE?=?size（X）;
N?=?SIZE（1）;
M?=?SIZE（2）;
w?=?INIT?*?ones（M?1）;
loss?=?1/N*（X*w-y）‘*（X*w-y）?+?lam*sqrt（w‘*w）;
count?=?0;
%subplot（414）
while?delta?>=?LIMIT
????count?=?count+1;
????dw?=?2/N*X‘*X*w?-?2/N*X‘*y?+?lam*（w‘*w）^（-0.5）*w;
????w?=?w?-?learn_rate?*?dw;
????t?=?1/N*（X*w-y）‘*（X*w-y）?+?lam*sqrt（w‘*w）;
????delta?=?loss?-?t
????loss?=?t;
????%scatter（countdelta）;hold?on;
end
count

?屬性????????????大小?????日期????時(shí)間???名稱
-----------?---------??----------?-----??----
?????文件?????????224??2015-10-17?19:53??data.txt
?????文件?????????300??2015-11-11?22:56??descent.asv
?????文件?????????499??2015-11-12?18:33??descent.m
?????文件?????????994??2015-11-12?16:18??goodlambda.asv
?????文件????????1003??2015-11-12?17:23??goodlambda.m
?????文件???????27715??2015-10-17?11:33??poly_fit_sin.jpg
?????文件?????????780??2015-10-17?20:17??poly_sin.asv
?????文件?????????781??2015-11-08?17:29??poly_sin.m
?????文件?????????206??2015-10-17?19:57??produceData.m
?????文件???????20165??2015-10-17?19:38??regularization.jpg
?????文件???????24953??2015-10-17?20:27??regularization2.jpg
?????文件????????1003??2015-11-12?18:27??test_descent.m
?????文件?????????105??2015-10-17?19:31??tmp.m
?????文件?????????993??2015-11-17?20:21??x.mat