SemanticGraphs.cs

using System.Collections.Generic;
using System.Threading.Tasks;
using Waher.Persistence;
 
namespace Waher.Content.Semantic
{
    public static class SemanticGraphs
    {
        public static Task<InMemorySemanticCube> CreateInMemoryCube(ISemanticModel Model)
        {
            return InMemorySemanticCube.Create(Model);
        }
 
        public static void ClearTags(ISemanticModel Model)
        {
            foreach (ISemanticTriple Triple in Model)
            {
                Triple.Subject.Tag = null;
                Triple.Predicate.Tag = null;
                Triple.Object.Tag = null;
            }
        }
 
        public static async Task<SemanticGraph> GetGraph(ISemanticModel Model)
        {
            SemanticGraph Result = new SemanticGraph();
            IEnumerator<ISemanticTriple> e = Model.GetEnumerator();
 
            if (e is IAsyncEnumerator eAsync)
            {
                while (await eAsync.MoveNextAsync())
                    Result.Add(e.Current);
            }
            else
            {
                while (e.MoveNext())
                    Result.Add(e.Current);
            }
 
            return Result;
        }
 
        public static async Task<SemanticGraph[]> GetConnectedGraphs(ISemanticModel Model)
        {
            InMemorySemanticCube Cube = await InMemorySemanticCube.Create(Model);
            return await GetConnectedGraphs(Model, Cube);
        }
 
        public static async Task<SemanticGraph[]> GetConnectedGraphs(ISemanticModel Model, ISemanticCube Cube)
        {
            Dictionary<ISemanticElement, int> Nodes = new Dictionary<ISemanticElement, int>();
            List<SemanticGraph> Graphs = new List<SemanticGraph>();
            LinkedList<ISemanticTriple> ToCheck = new LinkedList<ISemanticTriple>();
            SymmetricMatrix<bool> Connections = new SymmetricMatrix<bool>();
            int NrTraces = 0;
            int TraceNr;
 
            ClearTags(Model);
 
            foreach (ISemanticTriple Triple in Model)
            {
                if (Triple.Subject.Tag is null)
                {
                    if (Nodes.TryGetValue(Triple.Subject, out TraceNr))
                        Triple.Subject.Tag = TraceNr;
                    else
                    {
                        TraceNr = NrTraces++;
                        Triple.Subject.Tag = TraceNr;
                        Nodes[Triple.Subject] = TraceNr;
                        Connections[TraceNr, TraceNr] = true;
                    }
 
                    ToCheck.AddLast(Triple);
                }
                else if (Triple.Object.Tag is null)
                {
                    TraceNr = (int)Triple.Subject.Tag;
 
                    if (Triple.Object.IsLiteral)
                    {
                        Triple.Object.Tag = TraceNr;
                        continue;
                    }
 
                    if (Nodes.TryGetValue(Triple.Object, out int i))
                    {
                        if (i == TraceNr)
                            continue;
 
                        Connections[i, TraceNr] = true;
                        continue;
                    }
                    else
                    {
                        Triple.Object.Tag = TraceNr;
                        Nodes[Triple.Object] = TraceNr;
 
                        ISemanticPlane Plane = await Cube.GetTriplesByObject(Triple.Object);
 
                        foreach (ISemanticTriple T2 in Plane)
                            ToCheck.AddLast(T2);
                    }
                }
                else
                {
                    if (!Triple.Subject.Tag.Equals(Triple.Object.Tag))
                    {
                        TraceNr = (int)Triple.Subject.Tag;
                        int TraceNr2 = (int)Triple.Object.Tag;
 
                        Connections[TraceNr, TraceNr2] = true;
                    }
 
                    continue;
                }
 
                while (!(ToCheck.First is null))
                {
                    ISemanticTriple T = ToCheck.First.Value;
                    ToCheck.RemoveFirst();
 
                    if (T.Subject.Tag is null)
                    {
                        T.Subject.Tag = TraceNr;
 
                        if (Nodes.TryGetValue(T.Subject, out int i))
                        {
                            if (i != TraceNr)
                                Connections[i, TraceNr] = true;
                        }
                        else
                            Nodes[T.Subject] = TraceNr;
                    }
                    else
                    {
                        int i = (int)T.Subject.Tag;
                        if (i != TraceNr)
                            Connections[i, TraceNr] = true;
                    }
 
                    if (T.Object.Tag is null)
                    {
                        if (T.Object.IsLiteral)
                            T.Object.Tag = TraceNr;
                        else
                        {
                            if (Nodes.TryGetValue(T.Object, out int i))
                            {
                                if (i != TraceNr)
                                    Connections[i, TraceNr] = true;
                            }
                            else
                            {
                                T.Object.Tag = TraceNr;
                                Nodes[T.Object] = TraceNr;
 
                                ISemanticPlane Plane = await Cube.GetTriplesByObject(T.Object);
 
                                foreach (ISemanticTriple T2 in Plane)
                                    ToCheck.AddLast(T2);
                            }
                        }
                    }
                    else
                    {
                        int i = (int)T.Object.Tag;
                        if (i != TraceNr)
                            Connections[i, TraceNr] = true;
                    }
                }
            }
 
            Dictionary<int, SemanticGraph> GraphByTrace = new Dictionary<int, SemanticGraph>();
 
            while (NrTraces-- > 0)
            {
                if (!Connections[NrTraces, NrTraces])
                    continue;
 
                SortedDictionary<int, bool> Connected = new SortedDictionary<int, bool>();
                GetTraces(Connections, NrTraces, Connected);
 
                SemanticGraph Graph = new SemanticGraph();
                Graphs.Add(Graph);
 
                foreach (int i in Connected.Keys)
                    GraphByTrace[i] = Graph;
            }
 
            int LastTraceNr = -1;
            SemanticGraph LastGraph = null;
 
            foreach (ISemanticTriple Triple in Model)
            {
                TraceNr = (int)Triple.Subject.Tag;
 
                if (TraceNr != LastTraceNr)
                {
                    LastTraceNr = TraceNr;
                    LastGraph = GraphByTrace[TraceNr];
                }
 
                LastGraph.Add(Triple);
            }
 
            return Graphs.ToArray();
        }
 
        private static void GetTraces(SymmetricMatrix<bool> M, int TraceNr, SortedDictionary<int, bool> Elements)
        {
            int i;
 
            for (i = M.Size - 1; i >= 0; i--)
            {
                if (M[i, TraceNr])
                {
                    M[i, TraceNr] = false;
                    Elements[i] = true;
                    GetTraces(M, i, Elements);
                }
            }
        }
    }
}