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      1 //===-- Solution.h ------- PBQP Solution ------------------------*- C++ -*-===//
      2 //
      3 //                     The LLVM Compiler Infrastructure
      4 //
      5 // This file is distributed under the University of Illinois Open Source
      6 // License. See LICENSE.TXT for details.
      7 //
      8 //===----------------------------------------------------------------------===//
      9 //
     10 // PBQP Solution class.
     11 //
     12 //===----------------------------------------------------------------------===//
     13 
     14 #ifndef LLVM_CODEGEN_PBQP_SOLUTION_H
     15 #define LLVM_CODEGEN_PBQP_SOLUTION_H
     16 
     17 #include "Graph.h"
     18 #include "Math.h"
     19 #include <map>
     20 
     21 namespace PBQP {
     22 
     23   /// \brief Represents a solution to a PBQP problem.
     24   ///
     25   /// To get the selection for each node in the problem use the getSelection method.
     26   class Solution {
     27   private:
     28 
     29     typedef std::map<Graph::ConstNodeItr, unsigned,
     30                      NodeItrComparator> SelectionsMap;
     31     SelectionsMap selections;
     32 
     33     unsigned r0Reductions, r1Reductions, r2Reductions, rNReductions;
     34 
     35   public:
     36 
     37     /// \brief Initialise an empty solution.
     38     Solution()
     39       : r0Reductions(0), r1Reductions(0), r2Reductions(0), rNReductions(0) {}
     40 
     41     /// \brief Number of nodes for which selections have been made.
     42     /// @return Number of nodes for which selections have been made.
     43     unsigned numNodes() const { return selections.size(); }
     44 
     45     /// \brief Records a reduction via the R0 rule. Should be called from the
     46     ///        solver only.
     47     void recordR0() { ++r0Reductions; }
     48 
     49     /// \brief Returns the number of R0 reductions applied to solve the problem.
     50     unsigned numR0Reductions() const { return r0Reductions; }
     51 
     52     /// \brief Records a reduction via the R1 rule. Should be called from the
     53     ///        solver only.
     54     void recordR1() { ++r1Reductions; }
     55 
     56     /// \brief Returns the number of R1 reductions applied to solve the problem.
     57     unsigned numR1Reductions() const { return r1Reductions; }
     58 
     59     /// \brief Records a reduction via the R2 rule. Should be called from the
     60     ///        solver only.
     61     void recordR2() { ++r2Reductions; }
     62 
     63     /// \brief Returns the number of R2 reductions applied to solve the problem.
     64     unsigned numR2Reductions() const { return r2Reductions; }
     65 
     66     /// \brief Records a reduction via the RN rule. Should be called from the
     67     ///        solver only.
     68     void recordRN() { ++ rNReductions; }
     69 
     70     /// \brief Returns the number of RN reductions applied to solve the problem.
     71     unsigned numRNReductions() const { return rNReductions; }
     72 
     73     /// \brief Set the selection for a given node.
     74     /// @param nItr Node iterator.
     75     /// @param selection Selection for nItr.
     76     void setSelection(Graph::NodeItr nItr, unsigned selection) {
     77       selections[nItr] = selection;
     78     }
     79 
     80     /// \brief Get a node's selection.
     81     /// @param nItr Node iterator.
     82     /// @return The selection for nItr;
     83     unsigned getSelection(Graph::ConstNodeItr nItr) const {
     84       SelectionsMap::const_iterator sItr = selections.find(nItr);
     85       assert(sItr != selections.end() && "No selection for node.");
     86       return sItr->second;
     87     }
     88 
     89   };
     90 
     91 }
     92 
     93 #endif // LLVM_CODEGEN_PBQP_SOLUTION_H
     94