I came across a paper called A Few Useful Things to Know about Machine Learning which summarized some black arts in machine learning.

1. Learning = Representation + Evaluation + Optimization
2. It's generalization that counts
3. Data alone is not enough (we also need knowledge)
4. Overfitting has many faces
5. Intuition fails in high dimensions
6. Theoretical guarantee are not what they seem
7. Feature engineering is the …

LeetCode 137 is to find the number which apprears exactly once in an array assuming other numbers always appear exactly three times. It's very easy to come up with a linear runtime algorithm by using hash table which takes O(n) space. A better approach is to modulo count the number of occurrences of 1 at every bit and compose …

Introduction

I have been fiddling with MacBook Pro in the past few days. The Quartz Desktop is really awesome. MacOS has got some software supports as pretty as Windows. Graphical applications like Steam and BattleNet are available. But still I didn't get used to BSD toolchains.

At first thought, I told myself not to be so close-minded. So I tried …

Introduction

I got a MacBook Pro recently, the mid 2015 15" version. I have to admit that MacOs and Homebrew are cool. But still I want Gentoo Portage back. Actually I doubt if anyone can still date with other package system after you have seen the true beauty of Gentoo Portage. So I tried Gentoo Prefix. But unfortunately, at this …

说真的，当发现 Emacs 还不支持全彩色时，我还是有点吃惊的。毕竟很多程序都已经开始支 持了，比如 vim，neovim，konsole 等等。连 tmux 都从今年三月的 2.2 版本开始支持全彩色了。 没有全彩色支持对于 terminal 下工作的人来说，真的很不爽，像是 solarized 常用的主题颜 色在非全彩色情况下的退化表现一般都不是很理想。不过好在 emacs 上有全彩色的 patch，可 以实现这个小目标。

以 24.5 版本为例

curl https://goo.gl/a9qsIY > emacs-24.5-24bit.diff
wget http://gnu.mirrors.pair.com/gnu/emacs/emacs-24.5.tar.gz
tar xzf emacs-24.5 …