gSpan algorithm in data mining

Features:

1. Support basic sub-structure mining.
2. Multi-thread. (200% speed-up than gSpan-64 provided by Yan)
3. Minimized memory consumption.

Usage:

./gspan -file [file_name] -support [support: float] &> log

Progress:

1. MPI
2. Optimize the sequential version.
3. Detailed parallelism

12/4/2014

1. Reduce memory consumption.
2. Rearrange the gSpan class code.
3. Profling.
4. Multi-thread.