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