Tips for efficiency

[weixin_38081679]

1. make use of multi-core CPU:     if you have multi-core CPU, you can speed-up compiling of your code by doing the following:      make -j4 (if you have 2-core CPU) or      make -j5 (if you have 3-core CPU) or      make -j6 (if you have 4-core CPU)This is parallel compiling on one computer. To determine the number of cores in your CPU, use the following command      cat /proc/cpuinfo | grep processor | wc -lI define it in my shell as     alias numcpu='cat /proc/cpuinfo | grep processor | wc -l'2. use ccache    ccache can be installed on Ubuntu with      sudo apt-get install ccacheAfter this is done, make changes in the Makefile likeCC      = ccache gccCXX      = ccache g++When the code is recompiled, you will see clear speed-up.