public static Graph GenerateKekuleForm(Graph g, BitArray subset, BitArray aromatic, bool inplace)
{
// make initial (empty) matching - then improve it, first
// by matching the first edges we find, most of time this
// gives us a perfect matching if not we maximise it
// with Edmonds' algorithm
Matching m = Matching.CreateEmpty(g);
int n = BitArrays.Cardinality(subset);
int nMatched = ArbitraryMatching.Initial(g, m, subset);
if (nMatched < n)
{
if (n - nMatched == 2)
{
nMatched = ArbitraryMatching.AugmentOnce(g, m, nMatched, subset);
}
if (nMatched < n)
{
nMatched = MaximumMatching.Maximise(g, m, nMatched, IntSet.FromBitArray(subset));
}
if (nMatched < n)
{
throw new InvalidSmilesException("Could not Kekulise");
}
}
return(inplace ? Assign(g, subset, aromatic, m)
: CopyAndAssign(g, subset, aromatic, m));
}
public void Furan_2()
{
Graph g = Graph.FromSmiles("c1ccoc1");
Matching m = Matching.CreateEmpty(g);
ArbitraryMatching.Initial(g,
m,
AllOf(0, 1, 2, 4));
Assert.AreEqual(1, m.GetMatches().Count());
Assert.IsTrue(Compares.AreOrderLessDeepEqual(
new[] { Tuple.Of(0, 1) },
m.GetMatches()));
}
public void Furan()
{
Graph g = Graph.FromSmiles("o1cccc1");
Matching m = Matching.CreateEmpty(g);
ArbitraryMatching.Initial(g, m,
AllOf(1, 2, 3, 4));
// note this matching is maximum
Assert.AreEqual(2, m.GetMatches().Count());
Assert.IsTrue(Compares.AreOrderLessDeepEqual(
new[] { Tuple.Of(1, 2), Tuple.Of(3, 4) },
m.GetMatches()));
}
public void Benzene()
{
Graph g = Graph.FromSmiles("c1ccccc1");
Matching m = Matching.CreateEmpty(g);
ArbitraryMatching.Initial(g,
m,
AllOf(0, 1, 2, 3, 4, 5));
Assert.AreEqual(3, m.GetMatches().Count());
Assert.IsTrue(Compares.AreOrderLessDeepEqual(
new[] {
Tuple.Of(0, 1),
Tuple.Of(2, 3),
Tuple.Of(4, 5),
},
m.GetMatches()));
}
