src/Tuner/autotuner.cc

   1 #include "autotuner.h"
   2 #include "csolver.h"
   3 #include "searchtuner.h"
   4 #include <math.h>
   5 #include <stdlib.h>
   6 #include <float.h>
   7
   8 AutoTuner::AutoTuner(uint _budget) :
   9         budget(_budget) {
  10 }
  11
  12 void AutoTuner::addProblem(CSolver *solver) {
  13         solvers.push(solver);
  14 }
  15
  16 long long AutoTuner::evaluate(CSolver *problem, SearchTuner *tuner) {
  17         CSolver *copy = problem->clone();
  18         copy->setTuner(tuner);
  19         model_print("**********************\n");
  20         int result = copy->solve();
  21         //model_print("SAT %d\n", result);
  22         long long elapsedTime = copy->getElapsedTime();
  23 //      long long encodeTime = copy->getEncodeTime();
  24 //      long long solveTime = copy->getSolveTime();
  25         long long metric = elapsedTime;
  26 //      model_print("Elapsed Time: %llu\n", elapsedTime);
  27 //      model_print("Encode Time: %llu\n", encodeTime);
  28 //      model_print("Solve Time: %llu\n", solveTime);
  29         delete copy;
  30         return metric;
  31 }
  32
  33 double AutoTuner::evaluateAll(SearchTuner *tuner) {
  34         double product = 1;
  35         for (uint i = 0; i < solvers.getSize(); i++) {
  36                 CSolver *problem = solvers.get(i);
  37                 double score = evaluate(problem, tuner);
  38                 product *= score;
  39         }
  40         return pow(product, 1 / ((double)solvers.getSize()));
  41 }
  42
  43 SearchTuner *AutoTuner::mutateTuner(SearchTuner *oldTuner, uint k) {
  44         SearchTuner *newTuner = oldTuner->copyUsed();
  45         uint numSettings = oldTuner->getSize();
  46         double factor = 0.3;//Adjust this factor...
  47         uint settingsToMutate = (uint)(factor * (((double)numSettings) * (budget - k)) / (budget));
  48         if (settingsToMutate < 1)
  49                 settingsToMutate = 1;
  50         model_print("Mutating %u settings\n", settingsToMutate);
  51         while (settingsToMutate-- != 0) {
  52                 newTuner->randomMutate();
  53         }
  54         return newTuner;
  55 }
  56
  57
  58 void AutoTuner::tune() {
  59         SearchTuner *bestTuner = NULL;
  60         double bestScore = DBL_MAX;
  61
  62         SearchTuner *oldTuner = new SearchTuner();
  63         double base_temperature = evaluateAll(oldTuner);
  64         double oldScore = base_temperature;
  65
  66         for (uint i = 0; i < budget; i++) {
  67                 SearchTuner *newTuner = mutateTuner(oldTuner, i);
  68                 double newScore = evaluateAll(newTuner);
  69                 newTuner->printUsed();
  70                 model_print("Received score %f\n", newScore);
  71                 double scoreDiff = newScore - oldScore; //smaller is better
  72                 if (newScore < bestScore) {
  73                         if (bestTuner != NULL)
  74                                 delete bestTuner;
  75                         bestScore = newScore;
  76                         bestTuner = newTuner->copyUsed();
  77                 }
  78
  79                 double acceptanceP;
  80                 if (scoreDiff < 0) {
  81                         acceptanceP = 1;
  82                 } else {
  83                         double currTemp = base_temperature * (((double)budget - i) / budget);
  84                         acceptanceP = exp(-scoreDiff / currTemp);
  85                 }
  86                 double ran = ((double)random()) / RAND_MAX;
  87                 if (ran <= acceptanceP) {
  88                         delete oldTuner;
  89                         oldScore = newScore;
  90                         oldTuner = newTuner;
  91                 } else {
  92                         delete newTuner;
  93                 }
  94         }
  95         model_print("Best tuner:\n");
  96         bestTuner->print();
  97         model_print("Received score %f\n", bestScore);
  98         if (bestTuner != NULL)
  99                 delete bestTuner;
 100         delete oldTuner;
 101 }