private void initializeArrowsBackward(Graph graph) { sortedArrows.clear(); lookupArrows.clear(); for (Edge edge : graph.getEdges()) { Node x = edge.getNode1(); Node y = edge.getNode2(); if (!knowledgeEmpty()) { if (!getKnowledge().noEdgeRequired(x.getName(), y.getName())) { continue; } } if (Edges.isDirectedEdge(edge)) { calculateArrowsBackward(x, y, graph); } else { calculateArrowsBackward(x, y, graph); calculateArrowsBackward(y, x, graph); } } }