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790 lines
23 KiB
C++
790 lines
23 KiB
C++
//===-- HeuristicSolver.h - Heuristic PBQP Solver --------------*- C++ --*-===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// Heuristic PBQP solver. This solver is able to perform optimal reductions for
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// nodes of degree 0, 1 or 2. For nodes of degree >2 a plugable heuristic is
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// used to to select a node for reduction.
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//
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//===----------------------------------------------------------------------===//
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#ifndef LLVM_CODEGEN_PBQP_HEURISTICSOLVER_H
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#define LLVM_CODEGEN_PBQP_HEURISTICSOLVER_H
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#include "Solver.h"
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#include "AnnotatedGraph.h"
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#include "llvm/Support/raw_ostream.h"
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#include <limits>
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namespace PBQP {
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/// \brief Important types for the HeuristicSolverImpl.
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///
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/// Declared seperately to allow access to heuristic classes before the solver
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/// is fully constructed.
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template <typename HeuristicNodeData, typename HeuristicEdgeData>
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class HSITypes {
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public:
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class NodeData;
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class EdgeData;
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typedef AnnotatedGraph<NodeData, EdgeData> SolverGraph;
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typedef typename SolverGraph::NodeIterator GraphNodeIterator;
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typedef typename SolverGraph::EdgeIterator GraphEdgeIterator;
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typedef typename SolverGraph::AdjEdgeIterator GraphAdjEdgeIterator;
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typedef std::list<GraphNodeIterator> NodeList;
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typedef typename NodeList::iterator NodeListIterator;
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typedef std::vector<GraphNodeIterator> NodeStack;
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typedef typename NodeStack::iterator NodeStackIterator;
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class NodeData {
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friend class EdgeData;
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private:
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typedef std::list<GraphEdgeIterator> LinksList;
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unsigned numLinks;
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LinksList links, solvedLinks;
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NodeListIterator bucketItr;
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HeuristicNodeData heuristicData;
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public:
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typedef typename LinksList::iterator AdjLinkIterator;
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private:
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AdjLinkIterator addLink(const GraphEdgeIterator &edgeItr) {
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++numLinks;
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return links.insert(links.end(), edgeItr);
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}
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void delLink(const AdjLinkIterator &adjLinkItr) {
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--numLinks;
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links.erase(adjLinkItr);
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}
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public:
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NodeData() : numLinks(0) {}
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unsigned getLinkDegree() const { return numLinks; }
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HeuristicNodeData& getHeuristicData() { return heuristicData; }
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const HeuristicNodeData& getHeuristicData() const {
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return heuristicData;
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}
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void setBucketItr(const NodeListIterator &bucketItr) {
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this->bucketItr = bucketItr;
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}
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const NodeListIterator& getBucketItr() const {
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return bucketItr;
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}
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AdjLinkIterator adjLinksBegin() {
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return links.begin();
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}
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AdjLinkIterator adjLinksEnd() {
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return links.end();
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}
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void addSolvedLink(const GraphEdgeIterator &solvedLinkItr) {
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solvedLinks.push_back(solvedLinkItr);
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}
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AdjLinkIterator solvedLinksBegin() {
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return solvedLinks.begin();
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}
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AdjLinkIterator solvedLinksEnd() {
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return solvedLinks.end();
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}
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};
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class EdgeData {
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private:
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SolverGraph &g;
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GraphNodeIterator node1Itr, node2Itr;
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HeuristicEdgeData heuristicData;
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typename NodeData::AdjLinkIterator node1ThisEdgeItr, node2ThisEdgeItr;
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public:
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EdgeData(SolverGraph &g) : g(g) {}
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HeuristicEdgeData& getHeuristicData() { return heuristicData; }
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const HeuristicEdgeData& getHeuristicData() const {
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return heuristicData;
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}
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void setup(const GraphEdgeIterator &thisEdgeItr) {
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node1Itr = g.getEdgeNode1Itr(thisEdgeItr);
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node2Itr = g.getEdgeNode2Itr(thisEdgeItr);
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node1ThisEdgeItr = g.getNodeData(node1Itr).addLink(thisEdgeItr);
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node2ThisEdgeItr = g.getNodeData(node2Itr).addLink(thisEdgeItr);
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}
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void unlink() {
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g.getNodeData(node1Itr).delLink(node1ThisEdgeItr);
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g.getNodeData(node2Itr).delLink(node2ThisEdgeItr);
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}
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};
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};
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template <typename Heuristic>
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class HeuristicSolverImpl {
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public:
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// Typedefs to make life easier:
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typedef HSITypes<typename Heuristic::NodeData,
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typename Heuristic::EdgeData> HSIT;
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typedef typename HSIT::SolverGraph SolverGraph;
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typedef typename HSIT::NodeData NodeData;
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typedef typename HSIT::EdgeData EdgeData;
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typedef typename HSIT::GraphNodeIterator GraphNodeIterator;
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typedef typename HSIT::GraphEdgeIterator GraphEdgeIterator;
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typedef typename HSIT::GraphAdjEdgeIterator GraphAdjEdgeIterator;
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typedef typename HSIT::NodeList NodeList;
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typedef typename HSIT::NodeListIterator NodeListIterator;
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typedef std::vector<GraphNodeIterator> NodeStack;
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typedef typename NodeStack::iterator NodeStackIterator;
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/// \brief Constructor, which performs all the actual solver work.
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HeuristicSolverImpl(const SimpleGraph &orig) :
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solution(orig.getNumNodes(), true)
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{
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copyGraph(orig);
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simplify();
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setup();
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computeSolution();
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computeSolutionCost(orig);
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}
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/// \brief Returns the graph for this solver.
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SolverGraph& getGraph() { return g; }
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/// \brief Return the solution found by this solver.
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const Solution& getSolution() const { return solution; }
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private:
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/// \brief Add the given node to the appropriate bucket for its link
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/// degree.
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void addToBucket(const GraphNodeIterator &nodeItr) {
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NodeData &nodeData = g.getNodeData(nodeItr);
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switch (nodeData.getLinkDegree()) {
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case 0: nodeData.setBucketItr(
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r0Bucket.insert(r0Bucket.end(), nodeItr));
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break;
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case 1: nodeData.setBucketItr(
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r1Bucket.insert(r1Bucket.end(), nodeItr));
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break;
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case 2: nodeData.setBucketItr(
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r2Bucket.insert(r2Bucket.end(), nodeItr));
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break;
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default: heuristic.addToRNBucket(nodeItr);
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break;
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}
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}
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/// \brief Remove the given node from the appropriate bucket for its link
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/// degree.
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void removeFromBucket(const GraphNodeIterator &nodeItr) {
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NodeData &nodeData = g.getNodeData(nodeItr);
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switch (nodeData.getLinkDegree()) {
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case 0: r0Bucket.erase(nodeData.getBucketItr()); break;
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case 1: r1Bucket.erase(nodeData.getBucketItr()); break;
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case 2: r2Bucket.erase(nodeData.getBucketItr()); break;
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default: heuristic.removeFromRNBucket(nodeItr); break;
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}
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}
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public:
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/// \brief Add a link.
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void addLink(const GraphEdgeIterator &edgeItr) {
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g.getEdgeData(edgeItr).setup(edgeItr);
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if ((g.getNodeData(g.getEdgeNode1Itr(edgeItr)).getLinkDegree() > 2) ||
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(g.getNodeData(g.getEdgeNode2Itr(edgeItr)).getLinkDegree() > 2)) {
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heuristic.handleAddLink(edgeItr);
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}
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}
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/// \brief Remove link, update info for node.
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///
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/// Only updates information for the given node, since usually the other
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/// is about to be removed.
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void removeLink(const GraphEdgeIterator &edgeItr,
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const GraphNodeIterator &nodeItr) {
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if (g.getNodeData(nodeItr).getLinkDegree() > 2) {
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heuristic.handleRemoveLink(edgeItr, nodeItr);
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}
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g.getEdgeData(edgeItr).unlink();
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}
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/// \brief Remove link, update info for both nodes. Useful for R2 only.
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void removeLinkR2(const GraphEdgeIterator &edgeItr) {
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GraphNodeIterator node1Itr = g.getEdgeNode1Itr(edgeItr);
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if (g.getNodeData(node1Itr).getLinkDegree() > 2) {
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heuristic.handleRemoveLink(edgeItr, node1Itr);
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}
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removeLink(edgeItr, g.getEdgeNode2Itr(edgeItr));
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}
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/// \brief Removes all links connected to the given node.
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void unlinkNode(const GraphNodeIterator &nodeItr) {
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NodeData &nodeData = g.getNodeData(nodeItr);
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typedef std::vector<GraphEdgeIterator> TempEdgeList;
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TempEdgeList edgesToUnlink;
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edgesToUnlink.reserve(nodeData.getLinkDegree());
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// Copy adj edges into a temp vector. We want to destroy them during
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// the unlink, and we can't do that while we're iterating over them.
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std::copy(nodeData.adjLinksBegin(), nodeData.adjLinksEnd(),
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std::back_inserter(edgesToUnlink));
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for (typename TempEdgeList::iterator
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edgeItr = edgesToUnlink.begin(), edgeEnd = edgesToUnlink.end();
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edgeItr != edgeEnd; ++edgeItr) {
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GraphNodeIterator otherNode = g.getEdgeOtherNode(*edgeItr, nodeItr);
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removeFromBucket(otherNode);
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removeLink(*edgeItr, otherNode);
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addToBucket(otherNode);
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}
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}
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/// \brief Push the given node onto the stack to be solved with
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/// backpropagation.
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void pushStack(const GraphNodeIterator &nodeItr) {
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stack.push_back(nodeItr);
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}
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/// \brief Set the solution of the given node.
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void setSolution(const GraphNodeIterator &nodeItr, unsigned solIndex) {
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solution.setSelection(g.getNodeID(nodeItr), solIndex);
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for (GraphAdjEdgeIterator adjEdgeItr = g.adjEdgesBegin(nodeItr),
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adjEdgeEnd = g.adjEdgesEnd(nodeItr);
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adjEdgeItr != adjEdgeEnd; ++adjEdgeItr) {
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GraphEdgeIterator edgeItr(*adjEdgeItr);
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GraphNodeIterator adjNodeItr(g.getEdgeOtherNode(edgeItr, nodeItr));
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g.getNodeData(adjNodeItr).addSolvedLink(edgeItr);
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}
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}
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private:
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SolverGraph g;
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Heuristic heuristic;
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Solution solution;
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NodeList r0Bucket,
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r1Bucket,
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r2Bucket;
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NodeStack stack;
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// Copy the SimpleGraph into an annotated graph which we can use for reduction.
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void copyGraph(const SimpleGraph &orig) {
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assert((g.getNumEdges() == 0) && (g.getNumNodes() == 0) &&
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"Graph should be empty prior to solver setup.");
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assert(orig.areNodeIDsValid() &&
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"Cannot copy from a graph with invalid node IDs.");
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std::vector<GraphNodeIterator> newNodeItrs;
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for (unsigned nodeID = 0; nodeID < orig.getNumNodes(); ++nodeID) {
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newNodeItrs.push_back(
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g.addNode(orig.getNodeCosts(orig.getNodeItr(nodeID)), NodeData()));
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}
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for (SimpleGraph::ConstEdgeIterator
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origEdgeItr = orig.edgesBegin(), origEdgeEnd = orig.edgesEnd();
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origEdgeItr != origEdgeEnd; ++origEdgeItr) {
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unsigned id1 = orig.getNodeID(orig.getEdgeNode1Itr(origEdgeItr)),
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id2 = orig.getNodeID(orig.getEdgeNode2Itr(origEdgeItr));
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g.addEdge(newNodeItrs[id1], newNodeItrs[id2],
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orig.getEdgeCosts(origEdgeItr), EdgeData(g));
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}
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// Assign IDs to the new nodes using the ordering from the old graph,
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// this will lead to nodes in the new graph getting the same ID as the
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// corresponding node in the old graph.
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g.assignNodeIDs(newNodeItrs);
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}
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// Simplify the annotated graph by eliminating independent edges and trivial
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// nodes.
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void simplify() {
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disconnectTrivialNodes();
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eliminateIndependentEdges();
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}
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// Eliminate trivial nodes.
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void disconnectTrivialNodes() {
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for (GraphNodeIterator nodeItr = g.nodesBegin(), nodeEnd = g.nodesEnd();
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nodeItr != nodeEnd; ++nodeItr) {
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if (g.getNodeCosts(nodeItr).getLength() == 1) {
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std::vector<GraphEdgeIterator> edgesToRemove;
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for (GraphAdjEdgeIterator adjEdgeItr = g.adjEdgesBegin(nodeItr),
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adjEdgeEnd = g.adjEdgesEnd(nodeItr);
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adjEdgeItr != adjEdgeEnd; ++adjEdgeItr) {
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GraphEdgeIterator edgeItr = *adjEdgeItr;
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if (g.getEdgeNode1Itr(edgeItr) == nodeItr) {
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GraphNodeIterator otherNodeItr = g.getEdgeNode2Itr(edgeItr);
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g.getNodeCosts(otherNodeItr) +=
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g.getEdgeCosts(edgeItr).getRowAsVector(0);
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}
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else {
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GraphNodeIterator otherNodeItr = g.getEdgeNode1Itr(edgeItr);
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g.getNodeCosts(otherNodeItr) +=
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g.getEdgeCosts(edgeItr).getColAsVector(0);
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}
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edgesToRemove.push_back(edgeItr);
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}
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while (!edgesToRemove.empty()) {
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g.removeEdge(edgesToRemove.back());
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edgesToRemove.pop_back();
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}
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}
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}
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}
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void eliminateIndependentEdges() {
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std::vector<GraphEdgeIterator> edgesToProcess;
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for (GraphEdgeIterator edgeItr = g.edgesBegin(), edgeEnd = g.edgesEnd();
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edgeItr != edgeEnd; ++edgeItr) {
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edgesToProcess.push_back(edgeItr);
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}
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while (!edgesToProcess.empty()) {
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tryToEliminateEdge(edgesToProcess.back());
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edgesToProcess.pop_back();
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}
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}
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void tryToEliminateEdge(const GraphEdgeIterator &edgeItr) {
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if (tryNormaliseEdgeMatrix(edgeItr)) {
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g.removeEdge(edgeItr);
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}
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}
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bool tryNormaliseEdgeMatrix(const GraphEdgeIterator &edgeItr) {
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Matrix &edgeCosts = g.getEdgeCosts(edgeItr);
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Vector &uCosts = g.getNodeCosts(g.getEdgeNode1Itr(edgeItr)),
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&vCosts = g.getNodeCosts(g.getEdgeNode2Itr(edgeItr));
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for (unsigned r = 0; r < edgeCosts.getRows(); ++r) {
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PBQPNum rowMin = edgeCosts.getRowMin(r);
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uCosts[r] += rowMin;
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if (rowMin != std::numeric_limits<PBQPNum>::infinity()) {
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edgeCosts.subFromRow(r, rowMin);
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}
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else {
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edgeCosts.setRow(r, 0);
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}
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}
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for (unsigned c = 0; c < edgeCosts.getCols(); ++c) {
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PBQPNum colMin = edgeCosts.getColMin(c);
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vCosts[c] += colMin;
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if (colMin != std::numeric_limits<PBQPNum>::infinity()) {
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edgeCosts.subFromCol(c, colMin);
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}
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else {
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edgeCosts.setCol(c, 0);
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}
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}
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return edgeCosts.isZero();
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}
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void setup() {
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setupLinks();
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heuristic.initialise(*this);
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setupBuckets();
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}
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void setupLinks() {
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for (GraphEdgeIterator edgeItr = g.edgesBegin(), edgeEnd = g.edgesEnd();
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edgeItr != edgeEnd; ++edgeItr) {
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g.getEdgeData(edgeItr).setup(edgeItr);
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}
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}
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void setupBuckets() {
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for (GraphNodeIterator nodeItr = g.nodesBegin(), nodeEnd = g.nodesEnd();
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nodeItr != nodeEnd; ++nodeItr) {
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addToBucket(nodeItr);
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}
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}
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void computeSolution() {
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assert(g.areNodeIDsValid() &&
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"Nodes cannot be added/removed during reduction.");
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reduce();
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computeTrivialSolutions();
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backpropagate();
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}
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void printNode(const GraphNodeIterator &nodeItr) {
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llvm::errs() << "Node " << g.getNodeID(nodeItr) << " (" << &*nodeItr << "):\n"
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<< " costs = " << g.getNodeCosts(nodeItr) << "\n"
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<< " link degree = " << g.getNodeData(nodeItr).getLinkDegree() << "\n"
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<< " links = [ ";
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for (typename HSIT::NodeData::AdjLinkIterator
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aeItr = g.getNodeData(nodeItr).adjLinksBegin(),
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aeEnd = g.getNodeData(nodeItr).adjLinksEnd();
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aeItr != aeEnd; ++aeItr) {
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llvm::errs() << "(" << g.getNodeID(g.getEdgeNode1Itr(*aeItr))
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<< ", " << g.getNodeID(g.getEdgeNode2Itr(*aeItr))
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<< ") ";
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}
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llvm::errs() << "]\n";
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}
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void dumpState() {
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llvm::errs() << "\n";
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for (GraphNodeIterator nodeItr = g.nodesBegin(), nodeEnd = g.nodesEnd();
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nodeItr != nodeEnd; ++nodeItr) {
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printNode(nodeItr);
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}
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NodeList* buckets[] = { &r0Bucket, &r1Bucket, &r2Bucket };
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for (unsigned b = 0; b < 3; ++b) {
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NodeList &bucket = *buckets[b];
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llvm::errs() << "Bucket " << b << ": [ ";
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for (NodeListIterator nItr = bucket.begin(), nEnd = bucket.end();
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nItr != nEnd; ++nItr) {
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llvm::errs() << g.getNodeID(*nItr) << " ";
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}
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llvm::errs() << "]\n";
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}
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llvm::errs() << "Stack: [ ";
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for (NodeStackIterator nsItr = stack.begin(), nsEnd = stack.end();
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nsItr != nsEnd; ++nsItr) {
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llvm::errs() << g.getNodeID(*nsItr) << " ";
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}
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llvm::errs() << "]\n";
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}
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void reduce() {
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bool reductionFinished = r1Bucket.empty() && r2Bucket.empty() &&
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heuristic.rNBucketEmpty();
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while (!reductionFinished) {
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if (!r1Bucket.empty()) {
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processR1();
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}
|
|
else if (!r2Bucket.empty()) {
|
|
processR2();
|
|
}
|
|
else if (!heuristic.rNBucketEmpty()) {
|
|
solution.setProvedOptimal(false);
|
|
solution.incRNReductions();
|
|
heuristic.processRN();
|
|
}
|
|
else reductionFinished = true;
|
|
}
|
|
|
|
};
|
|
|
|
void processR1() {
|
|
|
|
// Remove the first node in the R0 bucket:
|
|
GraphNodeIterator xNodeItr = r1Bucket.front();
|
|
r1Bucket.pop_front();
|
|
|
|
solution.incR1Reductions();
|
|
|
|
//llvm::errs() << "Applying R1 to " << g.getNodeID(xNodeItr) << "\n";
|
|
|
|
assert((g.getNodeData(xNodeItr).getLinkDegree() == 1) &&
|
|
"Node in R1 bucket has degree != 1");
|
|
|
|
GraphEdgeIterator edgeItr = *g.getNodeData(xNodeItr).adjLinksBegin();
|
|
|
|
const Matrix &edgeCosts = g.getEdgeCosts(edgeItr);
|
|
|
|
const Vector &xCosts = g.getNodeCosts(xNodeItr);
|
|
unsigned xLen = xCosts.getLength();
|
|
|
|
// Duplicate a little code to avoid transposing matrices:
|
|
if (xNodeItr == g.getEdgeNode1Itr(edgeItr)) {
|
|
GraphNodeIterator yNodeItr = g.getEdgeNode2Itr(edgeItr);
|
|
Vector &yCosts = g.getNodeCosts(yNodeItr);
|
|
unsigned yLen = yCosts.getLength();
|
|
|
|
for (unsigned j = 0; j < yLen; ++j) {
|
|
PBQPNum min = edgeCosts[0][j] + xCosts[0];
|
|
for (unsigned i = 1; i < xLen; ++i) {
|
|
PBQPNum c = edgeCosts[i][j] + xCosts[i];
|
|
if (c < min)
|
|
min = c;
|
|
}
|
|
yCosts[j] += min;
|
|
}
|
|
}
|
|
else {
|
|
GraphNodeIterator yNodeItr = g.getEdgeNode1Itr(edgeItr);
|
|
Vector &yCosts = g.getNodeCosts(yNodeItr);
|
|
unsigned yLen = yCosts.getLength();
|
|
|
|
for (unsigned i = 0; i < yLen; ++i) {
|
|
PBQPNum min = edgeCosts[i][0] + xCosts[0];
|
|
|
|
for (unsigned j = 1; j < xLen; ++j) {
|
|
PBQPNum c = edgeCosts[i][j] + xCosts[j];
|
|
if (c < min)
|
|
min = c;
|
|
}
|
|
yCosts[i] += min;
|
|
}
|
|
}
|
|
|
|
unlinkNode(xNodeItr);
|
|
pushStack(xNodeItr);
|
|
}
|
|
|
|
void processR2() {
|
|
|
|
GraphNodeIterator xNodeItr = r2Bucket.front();
|
|
r2Bucket.pop_front();
|
|
|
|
solution.incR2Reductions();
|
|
|
|
// Unlink is unsafe here. At some point it may optimistically more a node
|
|
// to a lower-degree list when its degree will later rise, or vice versa,
|
|
// violating the assumption that node degrees monotonically decrease
|
|
// during the reduction phase. Instead we'll bucket shuffle manually.
|
|
pushStack(xNodeItr);
|
|
|
|
assert((g.getNodeData(xNodeItr).getLinkDegree() == 2) &&
|
|
"Node in R2 bucket has degree != 2");
|
|
|
|
const Vector &xCosts = g.getNodeCosts(xNodeItr);
|
|
|
|
typename NodeData::AdjLinkIterator tempItr =
|
|
g.getNodeData(xNodeItr).adjLinksBegin();
|
|
|
|
GraphEdgeIterator yxEdgeItr = *tempItr,
|
|
zxEdgeItr = *(++tempItr);
|
|
|
|
GraphNodeIterator yNodeItr = g.getEdgeOtherNode(yxEdgeItr, xNodeItr),
|
|
zNodeItr = g.getEdgeOtherNode(zxEdgeItr, xNodeItr);
|
|
|
|
removeFromBucket(yNodeItr);
|
|
removeFromBucket(zNodeItr);
|
|
|
|
removeLink(yxEdgeItr, yNodeItr);
|
|
removeLink(zxEdgeItr, zNodeItr);
|
|
|
|
// Graph some of the costs:
|
|
bool flipEdge1 = (g.getEdgeNode1Itr(yxEdgeItr) == xNodeItr),
|
|
flipEdge2 = (g.getEdgeNode1Itr(zxEdgeItr) == xNodeItr);
|
|
|
|
const Matrix *yxCosts = flipEdge1 ?
|
|
new Matrix(g.getEdgeCosts(yxEdgeItr).transpose()) :
|
|
&g.getEdgeCosts(yxEdgeItr),
|
|
*zxCosts = flipEdge2 ?
|
|
new Matrix(g.getEdgeCosts(zxEdgeItr).transpose()) :
|
|
&g.getEdgeCosts(zxEdgeItr);
|
|
|
|
unsigned xLen = xCosts.getLength(),
|
|
yLen = yxCosts->getRows(),
|
|
zLen = zxCosts->getRows();
|
|
|
|
// Compute delta:
|
|
Matrix delta(yLen, zLen);
|
|
|
|
for (unsigned i = 0; i < yLen; ++i) {
|
|
for (unsigned j = 0; j < zLen; ++j) {
|
|
PBQPNum min = (*yxCosts)[i][0] + (*zxCosts)[j][0] + xCosts[0];
|
|
for (unsigned k = 1; k < xLen; ++k) {
|
|
PBQPNum c = (*yxCosts)[i][k] + (*zxCosts)[j][k] + xCosts[k];
|
|
if (c < min) {
|
|
min = c;
|
|
}
|
|
}
|
|
delta[i][j] = min;
|
|
}
|
|
}
|
|
|
|
if (flipEdge1)
|
|
delete yxCosts;
|
|
|
|
if (flipEdge2)
|
|
delete zxCosts;
|
|
|
|
// Deal with the potentially induced yz edge.
|
|
GraphEdgeIterator yzEdgeItr = g.findEdge(yNodeItr, zNodeItr);
|
|
if (yzEdgeItr == g.edgesEnd()) {
|
|
yzEdgeItr = g.addEdge(yNodeItr, zNodeItr, delta, EdgeData(g));
|
|
}
|
|
else {
|
|
// There was an edge, but we're going to screw with it. Delete the old
|
|
// link, update the costs. We'll re-link it later.
|
|
removeLinkR2(yzEdgeItr);
|
|
g.getEdgeCosts(yzEdgeItr) +=
|
|
(yNodeItr == g.getEdgeNode1Itr(yzEdgeItr)) ?
|
|
delta : delta.transpose();
|
|
}
|
|
|
|
bool nullCostEdge = tryNormaliseEdgeMatrix(yzEdgeItr);
|
|
|
|
// Nulled the edge, remove it entirely.
|
|
if (nullCostEdge) {
|
|
g.removeEdge(yzEdgeItr);
|
|
}
|
|
else {
|
|
// Edge remains - re-link it.
|
|
addLink(yzEdgeItr);
|
|
}
|
|
|
|
addToBucket(yNodeItr);
|
|
addToBucket(zNodeItr);
|
|
}
|
|
|
|
void computeTrivialSolutions() {
|
|
|
|
for (NodeListIterator r0Itr = r0Bucket.begin(), r0End = r0Bucket.end();
|
|
r0Itr != r0End; ++r0Itr) {
|
|
GraphNodeIterator nodeItr = *r0Itr;
|
|
|
|
solution.incR0Reductions();
|
|
setSolution(nodeItr, g.getNodeCosts(nodeItr).minIndex());
|
|
}
|
|
|
|
}
|
|
|
|
void backpropagate() {
|
|
while (!stack.empty()) {
|
|
computeSolution(stack.back());
|
|
stack.pop_back();
|
|
}
|
|
}
|
|
|
|
void computeSolution(const GraphNodeIterator &nodeItr) {
|
|
|
|
NodeData &nodeData = g.getNodeData(nodeItr);
|
|
|
|
Vector v(g.getNodeCosts(nodeItr));
|
|
|
|
// Solve based on existing links.
|
|
for (typename NodeData::AdjLinkIterator
|
|
solvedLinkItr = nodeData.solvedLinksBegin(),
|
|
solvedLinkEnd = nodeData.solvedLinksEnd();
|
|
solvedLinkItr != solvedLinkEnd; ++solvedLinkItr) {
|
|
|
|
GraphEdgeIterator solvedEdgeItr(*solvedLinkItr);
|
|
Matrix &edgeCosts = g.getEdgeCosts(solvedEdgeItr);
|
|
|
|
if (nodeItr == g.getEdgeNode1Itr(solvedEdgeItr)) {
|
|
GraphNodeIterator adjNode(g.getEdgeNode2Itr(solvedEdgeItr));
|
|
unsigned adjSolution =
|
|
solution.getSelection(g.getNodeID(adjNode));
|
|
v += edgeCosts.getColAsVector(adjSolution);
|
|
}
|
|
else {
|
|
GraphNodeIterator adjNode(g.getEdgeNode1Itr(solvedEdgeItr));
|
|
unsigned adjSolution =
|
|
solution.getSelection(g.getNodeID(adjNode));
|
|
v += edgeCosts.getRowAsVector(adjSolution);
|
|
}
|
|
|
|
}
|
|
|
|
setSolution(nodeItr, v.minIndex());
|
|
}
|
|
|
|
void computeSolutionCost(const SimpleGraph &orig) {
|
|
PBQPNum cost = 0.0;
|
|
|
|
for (SimpleGraph::ConstNodeIterator
|
|
nodeItr = orig.nodesBegin(), nodeEnd = orig.nodesEnd();
|
|
nodeItr != nodeEnd; ++nodeItr) {
|
|
|
|
unsigned nodeId = orig.getNodeID(nodeItr);
|
|
|
|
cost += orig.getNodeCosts(nodeItr)[solution.getSelection(nodeId)];
|
|
}
|
|
|
|
for (SimpleGraph::ConstEdgeIterator
|
|
edgeItr = orig.edgesBegin(), edgeEnd = orig.edgesEnd();
|
|
edgeItr != edgeEnd; ++edgeItr) {
|
|
|
|
SimpleGraph::ConstNodeIterator n1 = orig.getEdgeNode1Itr(edgeItr),
|
|
n2 = orig.getEdgeNode2Itr(edgeItr);
|
|
unsigned sol1 = solution.getSelection(orig.getNodeID(n1)),
|
|
sol2 = solution.getSelection(orig.getNodeID(n2));
|
|
|
|
cost += orig.getEdgeCosts(edgeItr)[sol1][sol2];
|
|
}
|
|
|
|
solution.setSolutionCost(cost);
|
|
}
|
|
|
|
};
|
|
|
|
template <typename Heuristic>
|
|
class HeuristicSolver : public Solver {
|
|
public:
|
|
Solution solve(const SimpleGraph &g) const {
|
|
HeuristicSolverImpl<Heuristic> solverImpl(g);
|
|
return solverImpl.getSolution();
|
|
}
|
|
};
|
|
|
|
}
|
|
|
|
#endif // LLVM_CODEGEN_PBQP_HEURISTICSOLVER_H
|