In psplib.tar.gz are some RCPSP instances downloaded from https://www.om-db.wi.tum.de/psplib/data.html, which is a subset of PSPLIB dataset [1]. 
This tarball should be extracted before running our program.

[1] Kolisch, Rainer, and Arno Sprecher. “PSPLIB - A Project Scheduling Problem Library: OR Software - ORSEP Operations Research Software Exchange Program.” European Journal of Operational Research 96, no. 1 (January 10, 1997): 205–16. https://doi.org/10.1016/S0377-2217(96)00170-1.
