Popularity-Similarity random model for SAT instances

Please, read and cite the detailed description in:

@inproceedings{ijcai17,
  author 	= {Jes{\'u}s Gir{\'a}ldez{-}Cru and Jordi Levy},
  title 	= {Locality in Random {SAT} Instances},
  booktitle 	= {Proc. of the 26th Int. Joint Conf. on Artificial Intelligence, IJCAI'17},
  year 		= {2017},
  pages     	= {638--644},	
}

Compilation:
 $ make all

Description/Help:
 $ ./ps-sat -h

c Popularity-Similarity SAT Instance Generator
c Created by Jesús Giráldez Crú and Jordi Levy
c
c Usage: ./ps-sat [arguments]
c    Arguments:
c         -n <int>   : number of nodes (default=100)
c         -m <int>   : number of clauses (default=400)
c         -k <int>   : average clause size (default=0)
c         -K <int>   : clause size for regular model (default=0)
c         -b <float> : beta for variables (default=1)
c         -B <float> : beta for clauses (default=1)
c         -T <float> : temperature (default=0)
c         -r         : varRename variables and reorder clauses so similar ones are closer (default=false)
c         -s <int>   : random seed (default=0)
c         -g         : print graph instead of CNF (default=false)
c