BP 网络通过微积分中的链法则来计算偏导数。这里我给出训练 BP 网络的公 式，详细的推导过程请见参考文献-BP network through calculus chain of rules to calculate partial derivatives. Here I give BP network training, the formula detailed derivation see References
SHOW FULL COLUMNS FROM `jrk_downrecords` [ RunTime:0.001211s ]
SELECT `a`.`aid`,`a`.`title`,`a`.`create_time`,`m`.`username` FROM `jrk_downrecords` `a` INNER JOIN `jrk_member` `m` ON `a`.`uid`=`m`.`id` WHERE `a`.`status` = 1 GROUP BY `a`.`aid` ORDER BY `a`.`create_time` DESC LIMIT 10 [ RunTime:0.098346s ]
SHOW FULL COLUMNS FROM `jrk_tagrecords` [ RunTime:0.001177s ]
SELECT * FROM `jrk_tagrecords` WHERE `status` = 1 ORDER BY `num` DESC LIMIT 20 [ RunTime:0.001887s ]
SHOW FULL COLUMNS FROM `jrk_member` [ RunTime:0.001206s ]
SELECT `id`,`username`,`userhead`,`usertime` FROM `jrk_member` WHERE `status` = 1 ORDER BY `usertime` DESC LIMIT 10 [ RunTime:0.003597s ]
SHOW FULL COLUMNS FROM `jrk_searchrecords` [ RunTime:0.001026s ]
SELECT * FROM `jrk_searchrecords` WHERE `status` = 1 ORDER BY `num` DESC LIMIT 5 [ RunTime:0.003183s ]
SELECT aid,title,count(aid) as c FROM `jrk_downrecords` GROUP BY `aid` ORDER BY `c` DESC LIMIT 10 [ RunTime:0.014231s ]
SHOW FULL COLUMNS FROM `jrk_articles` [ RunTime:0.001306s ]
UPDATE `jrk_articles` SET `hits` = 1 WHERE `id` = 113865 [ RunTime:0.001488s ]
