// ReSharper disable once UnusedParameter.Local
bool FValidDegrees(int ivtx1, int ivtx2)
{
// We must always have the degrees in graph1 at least as large as those in graph2. Also,
// since we order the vertices by total degree size, when we fail this condition, we know that
// there are no further vertices in graph1 which will match the current graph2 vertex so we can
// abandon the search.
return _vfs.FnCompareDegrees(_vfs.VfGraph1.InDegree(ivtx1) + _vfs.VfGraph1.OutDegree(ivtx1), _totalDegree2);
}
/// <summary>
/// Find a candidate graph2 vertex and the list of possible matches from graph1
/// </summary>
/// <remarks>
/// Find a candidate list from graph1 vertices for a particular graph2 vertex. If we've got vertices
/// in both out lists, take the first graph2 vertex in the outlist and use all the vertices in the
/// graph1 out list as candidates. If that doesn't work, do the same for the two respective
/// in lists and finally for the vertices disconnected from the current isomorphism.
/// </remarks>
/// <param name="vfs">State to grab vertices from</param>
internal CandidateFinder(VfState<TVAttr, TEAttr> vfs)
{
_vfs = vfs;
// Check to see if degrees are valid - this is only available because we sort the vertices
// by degree
if (
!vfs.FnCompareDegrees(vfs.LstOut1.Count, vfs.LstOut2.Count) ||
!vfs.FnCompareDegrees(vfs.LstIn1.Count, vfs.LstIn2.Count) ||
!vfs.FnCompareDegrees(vfs.LstDisconnected1.Count, vfs.LstDisconnected2.Count))
{
// Life isn't worth living - signal to ourselves to fail at the first call to
// NextCandidateMatch().
_fFailImmediately = true;
return;
}
// Try to find a match in vertices pointed to from the isomorphism
if (vfs.LstOut2.Count > 0 && vfs.LstOut1.Count > 0)
{
_graph1Candidates = new int[vfs.LstOut1.Count];
vfs.LstOut1.CopyTo(_graph1Candidates);
SetInitialMatch(vfs.LstOut1[0], vfs.LstOut2[0]);
}
// Try to find a match in vertices pointing into the isomorphism
else if (vfs.LstIn2.Count > 0 && vfs.LstIn1.Count > 0)
{
_graph1Candidates = new int[vfs.LstIn1.Count];
vfs.LstIn1.CopyTo(_graph1Candidates);
SetInitialMatch(vfs.LstIn1[0], vfs.LstIn2[0]);
}
// Try to find a match in vertices unattached to the isomorphism
else if (vfs.LstDisconnected1.Count >= 0)
{
_graph1Candidates = new int[vfs.LstDisconnected1.Count];
vfs.LstDisconnected1.CopyTo(_graph1Candidates);
SetInitialMatch(vfs.LstDisconnected1[0], vfs.LstDisconnected2[0]);
}
}