3.17 照片

春假也没出远门，算是好好的休息了一回。好歹在放假快结束的时候出门透了透气。

fstream issue under 64-bits cygwin

This is a question I posted on StackOverflow: fstream issue under 64-bits cygwin, glad to get help from Nemo on Stackflow, all credits goes to him. The problem is when I use 64-bits g++ to compile the same piece of code, I get unexpected different result. The source code looks like this: #include #include using […]

Use a different delimiter in sed

Think about this, you want to replace “XXX” with a path like “/path/to/YYY” in a file. Your file looks like this: XXX AAA XXX Your bash script looks like this: NEW_PATH=”/path/to/YYY” VAR=”XXX” sed -e ‘{s/$VAR/$NEW_PATH/g}’ your_file Well, it won’t work, since single quotes ‘ will force bash to keep variables as-is. Ok, we try to […]

STL map operator[] not const

STL里Map的Operator[]和其它的Container不太一样。因为Map的Operator[]可以提供这种操作: map testMap; testMap[“a”] = “b”; 所以Map的Operator[]返回的是T&，而不是const T& 如果需要得到const reference,可以这样: map testMap; const string& constMember = testMap.find(“a”)->second;

UnitTest框架GoogleTest

回到C++下，随着代码量增加，遇到维护问题了。找到一个Google的UnitTest框架，GoogleTest 有很详细的Sample，推荐一下 :] 编译的时候需要先编译出libgtest.a和gtest_main.o，自己的testXX.cpp文件需要和ligtest.a, gtest_main.o链接。 $g++ testXX.cpp path/to/gtest_main.o -Lpath/to/libgtest.a -lgtest -o testXX

Project-Specific Vim Configuration

Usually, we have our own vim configuration in the file ~/.vimrc What if we want one for our project? For example, we are working on certain project which needs to read in a tags file. Well, here is a possible solution. You put a line at then end of your ~/.vimrc file source ./.project.vim Then […]

tail -n

Quite useful trick, when you want to get rid of the first certain lines of the output/file. $tail -n +2 tail prints out the result starts from the 2nd line. When you use the “find” command to generate a file list under certain folder, this is quite easy to eliminate the folder path at the […]

Draw ROC Curve

A piece of fairly simple Matlab script to draw the ROC Curve from an array of scores and an array of labels. function [Tps, Fps] = ROC(scores, labels) %% Sort Labels and Scores by Scores sl = [scores; labels]; [d1 d2] = sort(sl(1,:)); sorted_sl = sl(:,d2); s_scores = sorted_sl(1,:); s_labels = round(sorted_sl(2,:)); %% Constants counts […]