DIMACS (cpmpy.tools.dimacs)

This file implements helper functions for exporting CPMpy models from and to DIMACS format. DIMACS is a textual format to represent CNF problems. The header of the file should be formatted as p cnf <n_vars> <n_constraints> If the number of variables and constraints are not given, it is inferred by the parser.

Each remaining line of the file is formatted as a list of integers. An integer represents a Boolean variable and a negative Boolean variable is represented using a - sign.

cpmpy.tools.dimacs.read_dimacs(fname)

Read a CPMpy model from a DIMACS formatted file If the number of variables and constraints is not present in the header, they are inferred. :param: fname: the name of the DIMACS file :param: sep: optional, separator used in the DIMACS file, will try to infer if None

cpmpy.tools.dimacs.write_dimacs(model, fname=None)

Writes CPMpy model to DIMACS format Uses the “to_cnf” transformation from CPMpy

# TODO: implement pseudoboolean constraints in to_cnf :param model: a CPMpy model :fname: optional, file name to write the DIMACS output to