NAUTY format
[Input-Output]

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Detailed Description

Tool to read graphs from Nauty format data

Files
file	nauty_reader.h
	Nauty file reader.
Functions
template<typename UGraph >
std::istream &	readNauty (std::istream &is, UGraph &ugraph)
	Nauty file reader.

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Function Documentation

std::istream& lemon::readNauty	(	std::istream &	is,
		UGraph &	ugraph
	)			[inline]

The geng program is in the gtools suite of the nauty package. This tool can generate all non-isomorphic undirected graphs with given node number from several classes (for example, general, connected, biconnected, triangle-free, 4-cycle-free, bipartite and graphs with given edge number and degree constraints). This function reads a nauty graph6 format line from the given stream and builds it in the given graph.

The site of nauty package: http://cs.anu.edu.au/~bdm/nauty/

For example, the number of all non-isomorphic connected graphs can be computed with next code:

      int num = 0;
      SmartUGraph ugraph;
      while(readNauty(std::cin, ugraph)) {
        PlanarityChecking<SmartUGraph> pc(ugraph);
        if (pc.run()) ++num;
      }
      std::cout << "Number of planar graphs: " << num << std::endl;

The nauty files are quite huge, therefore instead of the direct file generation the pipelining is recommended. The execution of this program:

      ./geng -c 10 | ./num_of_pg