/// <summary>
        /// Create a NeatGenome with the given meta data, connection genes and supplementary data.
        /// </summary>
        /// <param name="id">Genome ID.</param>
        /// <param name="birthGeneration">Birth generation.</param>
        /// <param name="connGenes">Connection genes.</param>
        /// <param name="hiddenNodeIdArr">An array of the hidden node IDs in the genome, in ascending order.</param>
        /// <returns>A new NeatGenome instance.</returns>
        public NeatGenome <T> Create(
            int id, int birthGeneration,
            ConnectionGenes <T> connGenes,
            int[] hiddenNodeIdArr)
        {
            int inputCount       = _metaNeatGenome.InputNodeCount;
            int outputCount      = _metaNeatGenome.OutputNodeCount;
            int inputOutputCount = _metaNeatGenome.InputOutputNodeCount;

            // Create a mapping from node IDs to node indexes.
            Dictionary <int, int> nodeIdxById = BuildNodeIndexById(hiddenNodeIdArr);

            // Create a DictionaryNodeIdMap.
            DictionaryNodeIdMap nodeIndexByIdMap = new DictionaryNodeIdMap(inputCount, nodeIdxById);

            // Create a digraph from the genome.
            DirectedGraph digraph = NeatGenomeBuilderUtils.CreateDirectedGraph(
                _metaNeatGenome, connGenes, nodeIndexByIdMap);

            // Calc the depth of each node in the digraph.
            GraphDepthInfo depthInfo = _graphDepthAnalysis.CalculateNodeDepths(digraph);

            // Create a weighted acyclic digraph.
            // Note. This also outputs connectionIndexMap. For each connection in the acyclic graph this gives
            // the index of the same connection in the genome; this is because connections are re-ordered based
            // on node depth in the acyclic graph.
            AcyclicDirectedGraph acyclicDigraph = AcyclicDirectedGraphBuilderUtils.CreateAcyclicDirectedGraph(
                digraph,
                depthInfo,
                out int[] newIdByOldId,
                out int[] connectionIndexMap,
                ref _timesortWorkArr,
                ref _timesortWorkVArr);

            // TODO: Write unit tests to cover this!
            // Update nodeIdxById with the new depth based node index allocations.
            // Notes.
            // The current nodeIndexByIdMap maps node IDs (also know as innovation IDs in NEAT) to a compact
            // ID space in which any gaps have been removed, i.e. a compacted set of IDs that can be used as indexes,
            // i.e. if there are N nodes in total then the highest node ID will be N-1.
            //
            // Here we map the new compact IDs to an alternative ID space that is also compact, but ensures that nodeIDs
            // reflect the depth of a node in the acyclic graph.
            UpdateNodeIndexById(nodeIdxById, hiddenNodeIdArr, newIdByOldId);

            // Create the neat genome.
            return(new NeatGenome <T>(
                       _metaNeatGenome, id, birthGeneration,
                       connGenes,
                       hiddenNodeIdArr,
                       nodeIndexByIdMap,
                       acyclicDigraph,
                       connectionIndexMap));
        }
        /// <summary>
        /// Create a NeatGenome with the given meta data, connection genes and supplementary data.
        /// </summary>
        /// <param name="id">Genome ID.</param>
        /// <param name="birthGeneration">Birth generation.</param>
        /// <param name="connGenes">Connection genes.</param>
        /// <param name="hiddenNodeIdArr">An array of the hidden node IDs in the genome, in ascending order.</param>
        /// <returns>A new NeatGenome instance.</returns>
        public NeatGenome <T> Create(
            int id, int birthGeneration,
            ConnectionGenes <T> connGenes,
            int[] hiddenNodeIdArr,
            INodeIdMap nodeIndexByIdMap)
        {
            // Create a digraph from the genome.
            DirectedGraph digraph = NeatGenomeBuilderUtils.CreateDirectedGraph(
                _metaNeatGenome, connGenes, nodeIndexByIdMap);

            return(new NeatGenome <T>(_metaNeatGenome, id, birthGeneration, connGenes, hiddenNodeIdArr, nodeIndexByIdMap, digraph, null));
        }