Author: Min Wang

  Somehow even wiki https://en.wikipedia.org/wiki/Bias%E2%80%93variance_tradeoff seems not clearly explained what it is due to un-cleary math denotion. Here we refer to: model/algorithm’s bias and variance ( not the data itself ).…

Theory background min: f0(x)         ==> p * s.t.:   fi(x) <= 0  i = 1, … m hi(x) = 0 ,  j= 1 … m define lagrange function:…

Generally how to write transaction Begin transaction by issuing the SQL command BEGIN WORK. Issue one or more SQL commands like SELECT, INSERT, UPDATE or DELETE. Check if there is no…

Screen screen -d -R your_session name //split only the monitor screen ctrl-a ( release the kb ), then press: | for vsplit    —> need this step : ctrl-a, c…

container name implementation/underlying struct notes/ sample unordered_set  The value of an element is at the same time its key, that identifies it uniquely. hash table unordered_multiset much like unordered_set containers, but allowing different…

Some good monitoring tools: homer: easy to install with docker for its server and install helifpy on a  sip/client/host : nohup ./heplify -hs homer_server:9060 & grep sngrep, ngrep pcap tcpdump/wireshark…

useful .vimrc set tabstop=2 set shiftwidth=2 set expandtab inoremap <S-Tab> <C-V><Tab> syntax on set t_Co=256 set colorcolumn=80 “crazy vim, do not allow copy/paste set mouse=v setlocal spell spelllang=en_us “for vert…

Compiled lang: src — compiler –> directly to machine code Interpreter( python/js) : src-> bytecode,   run on VM ( a VM load bytecode, and do some switch for each type…

Direct compile webrtc on arm64 will fail: webrtc seems does not support direct support on arm, we will get errors: … Running hooks: 18% ( 4/22) sysroot_arm64 ________ running ‘vpython…

nlohmann::json is a popluar json lib. code at: https://github.com/nlohmann/json document at: https://nlohmann.github.io/json/doxygen/index.html   sample code: #include <iostream> 2 #include <nlohmann/json.hpp> 3 4 using json = nlohmann::json; 5 6 int main() 7 { 8  //…