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