Failure reading DIMACS files with 10 variables or more

[natanaeljr]

Describe the bug

Reading DIMACS files fails with files having more than 10 variables from CNF.

Reproducible example code

main.cpp:

#include <lorina/common.hpp>
#include <tweedledum/Synthesis/pkrm_synth.h>
#include <kitty/dynamic_truth_table.hpp>
#include <mockturtle/networks/xag.hpp>
#include <mockturtle/io/dimacs_reader.hpp>
#include <tweedledum/Utils/Classical/xag_simulate.h>
#include <lorina/dimacs.hpp>

using namespace tweedledum;

int main()
{
  mockturtle::xag_network xag;
  lorina::return_code ret = lorina::read_dimacs("graphE.cnf", mockturtle::dimacs_reader(xag));
  if (ret != lorina::return_code::success)
    return 1;
  std::vector<kitty::dynamic_truth_table> truth_tables = xag_simulate(xag);
  Circuit circuit = pkrm_synth(truth_tables[0]);
  return 0;
}

graphE.cnf:

p cnf 12 31
1 2 3 0
4 5 6 0
7 8 9 0
10 11 12 0
-1 -2 0
-1 -3 0
-2 -3 0
-4 -5 0
-4 -6 0
-5 -6 0
-7 -8 0
-7 -9 0
-8 -9 0
-10 -11 0
-10 -12 0
-11 -12 0
-1 -4 0
-2 -5 0
-3 -6 0
-1 -7 0
-2 -8 0
-3 -9 0
-10 -1 0
-2 -11 0
-3 -12 0
-4 -7 0
-5 -8 0
-6 -9 0
-4 -10 0
-5 -11 0
-6 -12 0

Expected behavior

The DIMACS file is successfully read and the circuit is synthetized.

Information

• tweedledum version: v1.1.1
• Python version: v1.1.1
• C++ compiler: 13.2.1
• Operating system: Arch Linux

Additional context

Suggested fix for this issue:

diff --git a/external/lorina/lorina/dimacs.hpp b/external/lorina/lorina/dimacs.hpp
index dc44b9a..e8bd60f 100644
--- a/external/lorina/lorina/dimacs.hpp
+++ b/external/lorina/lorina/dimacs.hpp
@@ -99,7 +99,7 @@ public:
 namespace dimacs_regex
 {
 static std::regex problem_spec( R"(^p\s+([cd]nf)\s+([0-9]+)\s+([0-9]+)$)" );
-static std::regex clause( R"(((-?[1-9]+)+ +)+0)" );
+static std::regex clause( R"(((-?[1-9][0-9]*)+ +)+0)" );
 
 } // namespace dimacs_regex