利用pulp解決線性規劃問題

環境 # CentOS 安裝JPEGOTIM # 1yum install jpegoptim 壓縮命令 # 1jpegoptim image.jpg 批量壓縮 # 1for i in *.jpg; do jpegoptim $i; done 2find . -type f -name "*.jpg" -exec jpegoptim {} \;

本站突然發生 HTTP502 錯誤，導致幾天不能訪問，又適逢勞動節休假，Y.CHEUNG 沒帶電腦，而且縂想著反正訪問量極低，也就不趕著修復站點，今日才來細細察看一番。

最近設計的數據庫表含有外鍵，結果在開發時truncate table的時候報錯了， 1SQL错误（1701）：Cannot truncate a table referenced in a foreign key constraint (`rollcall2`.`oncall`, CONSTRAINT `FK__calls` FOREIGN KEY (`calls_id`) REFERENCES `rollcall2`.`calls` (`id`)) 解決辦法如下： 1SET FOREIGN_KEY_CHECKS = 0; 2TRUNCATE table; 3SET FOREIGN_KEY_CHECKS = 1; 當然也可以通過移除外鍵之類的辦法，但是感覺還是用上面幾行命令來解決比較方便。

系统：CentOS 7 文件系统：EXT4 今天 YCHEUNG 不小心用 rm 命令误删了一个名字奇奇怪怪的文件，因为名字太奇怪想不起来它是啥，怕是重要文件，所以急急忙忙去找办法恢复。

系统环境: Fedora 24 Node v4.5.0 NPM v2.15.9 NPM安装electron-builder报错 # 1$npm install electron-builder --save=dev 2npm WARN package.json [email protected] No repository field. 3npm WARN package.json [email protected] No README data 4 5> [email protected] install /var/www/html/test/node_modules/dev/node_modules/inotify 6> node-gyp rebuild 7 8make: Entering directory '/var/www/html/test/node_modules/dev/node_modules/inotify/build' 9 CXX(target) Release/obj.target/inotify/src/bindings.o 10make: g++：命令未找到 11inotify.target.mk:97: recipe for target 'Release/obj.target/inotify/src/bindings.o' failed 12make: *** [Release/obj.target/inotify/src/bindings.o] Error 127 13make: Leaving directory '/var/www/html/test/node_modules/dev/node_modules/inotify/build' 14gyp ERR! build error 15gyp ERR! stack Error: `make` failed with exit code: 2 16gyp ERR! stack at ChildProcess.onExit (/usr/lib/node_modules/npm/node_modules.bundled/node-gyp/lib/build.js:276:23) 17gyp ERR! stack at emitTwo (events.js:87:13) 18gyp ERR! stack at ChildProcess.emit (events.js:172:7) 19gyp ERR! stack at Process.ChildProcess._handle.onexit (internal/child_process.js:200:12) 20gyp ERR! System Linux 4.7.4-200.fc24.x86_64 21gyp ERR! command "/usr/bin/node" "/usr/lib/node_modules/npm/node_modules/node-gyp/bin/node-gyp.js" "rebuild" 22gyp ERR! cwd /var/www/html/test/node_modules/dev/node_modules/inotify 23gyp ERR! node -v v4.5.0 24gyp ERR! node-gyp -v v3.4.0 25gyp ERR! not ok 26npm WARN optional dep failed, continuing [email protected] 27npm WARN deprecated [email protected]: This package is deprecated. Use Object.assign. 28npm WARN optional dep failed, continuing [email protected] 29npm WARN optional dep failed, continuing [email protected] 30npm ERR! Linux 4.7.4-200.fc24.x86_64 31npm ERR! argv "/usr/bin/node" "/usr/bin/npm" "install" "electron-builder" "--save=dev" 32npm ERR! node v4.5.0 33npm ERR! npm v2.15.9 34npm ERR! code ELIFECYCLE 35 36npm ERR! [email protected] install: `node-gyp rebuild` 37npm ERR! Exit status 1 38npm ERR! 39npm ERR! Failed at the [email protected] install script 'node-gyp rebuild'. 40npm ERR! This is most likely a problem with the inotify package, 41npm ERR! not with npm itself. 42npm ERR! Tell the author that this fails on your system: 43npm ERR! node-gyp rebuild 44npm ERR! You can get information on how to open an issue for this project with: 45npm ERR! npm bugs inotify 46npm ERR! Or if that isn't available, you can get their info via: 47npm ERR! 48npm ERR! npm owner ls inotify 49npm ERR! There is likely additional logging output above. 50 51npm ERR! Please include the following file with any support request: 52npm ERR! /var/www/html/test/npm-debug.log 解决方法： # 安装G++ $sudo dnf install gcc-c++

Media Play 設置 # Video Location 選擇 Absolute Path Or URL。 找到安卓設備SDCard的根目錄(ROOT PATH) # 如果電腦上安裝了adb工具，使用指令 adb shell echo $EXTERNAL_STORAGE 打印SD Card Root directory。 如果安卓設備上安裝了terminal工具，(比如Terminal Emulator for Android)，使用指令 ls 根據經驗篩選可能的目錄。 一般而言，SD卡的根目錄可能但不限於以下幾種： /mnt/sdcard /storage/sdcard0 /storage/sdcard /sdcard 設置權限 # 在 AndroidManifest.xml 文件中的<uses-sdk前添加以下語句： 1<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" /> 通常該文件位於Assets/Plugins/Android/文件夾內，該配置文件詳解請參閱官方文檔《App Manifest》（有中文版）。