Method allocateWithInitialMapping

Extensions/QMapping/SabreQMapping.cpp:417–607

    : AbstractQubitMapping(ag), m_look_ahead(mLookAhead), m_max_iterations(mIterations), m_max_random_mappings(mRandomMappings), m_swap_cnt(0){}

std::optional<SabreQAllocator::MappingAndNSwaps>
SabreQAllocator::allocateWithInitialMapping(const Mapping& initialMapping, DynamicQCircuitGraph cir_graph, 
	QPanda::QuantumMachine *qvm, ArchGraph::sRef arch_graph, bool issueInstructions)
{
	auto mapping = initialMapping;
    std::map<QNodeRef, uint32_t> reached;
    std::set<QNodeRef> pastLookAhead;
    uint32_t swapNum = 0;
    uint32_t step_index = 0;
    uint32_t cut_step_swap_size = 0;
	//std::set<std::pair<uint32_t, uint32_t>> unConnectedNode;	/* 记录当前层不可执行门的节点对 */
    while (true)
	{
		/*
		 * Handle logic gates that can be executed directly: execute_gate
		 */
        bool changed = false;		/**< Whether there is an executable gate to join the execute_gate_list */
        do 
		{
            changed = false;
			//unConnectedNode.clear();
            std::vector<pPressedCirNode> issueNodes;				/**< execute_gate_list */
			auto& front_layer = cir_graph.get_front_layer();	/**< Front-layer qubit gate set (i.e., both previous gates of both qubits are executed) */
			for (uint32_t _i = 0; _i < front_layer.size();)
			{
				const auto& cur_gate = *((front_layer[_i])->m_cur_node->m_iter);
				/* Get the logic gate dependency */
				auto deps = build_deps(cur_gate);
				if (!deps.empty())
				{
					auto dep = deps[0];
					uint32_t u = mapping[dep.mFrom], v = mapping[dep.mTo];

					/*
					 * Determine whether the physical qubits of two logical qubit mappings are directly connected to each other
					 * If so, it means that it can be executed directly to add the current logic gate to the execute_gate_list
					 * If not, it means that it cannot be directly executed, reserved, and subsequently inserted into the swap gate
					 */
					/* 若量子比特不相连，则加入 */
					if (!arch_graph->hasEdge(u, v) && !arch_graph->hasEdge(v, u)) {
						++_i;
						/*unConnectedNode.insert(std::make_pair(u, v));
						unConnectedNode.insert(std::make_pair(v, u));*/
						continue;
					}
				}
				
				issueNodes.emplace_back(front_layer[_i]);
				_i = front_layer.remove_node(_i);
				changed = true;
                ++step_index;
                cut_step_swap_size = 0;
			}

			/*
			 * Remapping
			 */
			if (issueInstructions)