public void TestScc()
{
// https://en.wikipedia.org/wiki/Strongly_connected_component
//
// Adjacency list of directed graph with 8 nodes:
//
// [1] -> 2
// [2] -> 3 -> 5 -> 6
// [3] -> 4 -> 7
// [4] -> 3 -> 8
// [5] -> 1 -> 6
// [6] -> 7
// [7] -> 6
// [8] -> 4 -> 7
//
// Adjacency matrix:
var A = SparseMatrix.OfRowMajor(8, 8, new double[8 * 8]
{
1, 1, 0, 0, 0, 0, 0, 0,
0, 1, 1, 0, 1, 1, 0, 0,
0, 0, 1, 1, 0, 0, 1, 0,
0, 0, 1, 1, 0, 0, 0, 1,
1, 0, 0, 0, 1, 1, 0, 0,
0, 0, 0, 0, 0, 1, 1, 0,
0, 0, 0, 0, 0, 1, 1, 0,
0, 0, 0, 1, 0, 0, 1, 1
});
int n = A.ColumnCount;
var scc = StronglyConnectedComponents.Generate(A);
var r = new int[] { 0, 3, 6, 8 };
var p = new int[] { 0, 1, 4, 2, 3, 7, 5, 6 };
Assert.AreEqual(scc.Blocks, 3);
CollectionAssert.AreEqual(scc.BlockPointers, r);
CollectionAssert.AreEqual(scc.Indices, p);
}