#16924: Read DIMACS files
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Reporter: malb | Owner:
Type: enhancement | Status: needs_review
Priority: major | Milestone: sage-6.4
Component: interfaces: | Resolution:
optional | Merged in:
Keywords: | Reviewers: Martin Albrecht
Authors: Travis Scholl | Work issues:
Report Upstream: N/A | Commit:
Branch: | 34d8f00f1175b40bb7274934d217261eab2025e0
u/tscholl2/read_dimacs_16924 | Stopgaps:
Dependencies: |
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Comment (by vdelecroix):
I hardly found specification for DIMACS files. In
http://people.sc.fsu.edu/~jburkardt/data/cnf/cnf.html they say several
things that you are not taking care of:
- the comments should only be at the begining
- there is one line starting with `p cnf NUM_VAR NUM_CLAUSES` (the same
format is used for other constraint satisfcation problems)
- a clause might extend on more than one line and a clause might start on
the same line as another one
In other words, as far as I understand, this would be valid
{{{
c hey
c ho
p cnf 3 2
1 -2 0 3
1 0
}}}
Moreover, it is written ''In some examples of CNF files, the rule that the
variables are numbered from 1 to N is not followed. The file might declare
that there are 10 variables, for instance, but allow them to be numbered 2
through 11.''
It would be nice if you know some link with the exact specification of the
format.
--
Ticket URL: <http://trac.sagemath.org/ticket/16924#comment:23>
Sage <http://www.sagemath.org>
Sage: Creating a Viable Open Source Alternative to Magma, Maple, Mathematica,
and MATLAB
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