When you want to optimize a program, you need to know what code to spend your time working on. This HOWTO explains the process of using a profiler called 'gprof' to find out which functions in a program you should spend your time optimizing.
Memory leaks are when memory is allocated, but never given up. In small, short programs, they're not a problem, but in large, long-running programs, these leaks pile up until your program eventually slows down or crashes. This HOWTO explains how to use 'mtrace' to help track down the sources of memory leaks in your code.
Coming soon: HOWTOs on creating R libraries, and calling C and Fortran code from R.