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 #define UNSETVALUE -1
   9 #define TIMEOUTSEC 60
  10 AutoTuner::AutoTuner(uint _budget) :
  11         budget(_budget), result(UNSETVALUE) {
  12 }
  13
  14 void AutoTuner::addProblem(CSolver *solver) {
  15         solvers.push(solver);
  16 }
  17
  18 long long AutoTuner::evaluate(CSolver *problem, SearchTuner *tuner) {
  19         CSolver *copy = problem->clone();
  20         copy->setTuner(tuner);
  21         copy->setSatSolverTimeout(TIMEOUTSEC);
  22         model_print("**********************\n");
  23         int sat = copy->solve();
  24         if (result == UNSETVALUE && sat != IS_INDETER)
  25                 result = sat;
  26         else if (result != sat && sat != IS_INDETER) {
  27                 model_print("&&&&&&&&&&&&&&&&&& Result has changed &&&&&&&&&&&&&\n");
  28                 copy->printConstraints();
  29         }
  30         long long metric = copy->getElapsedTime();
  31         delete copy;
  32         return metric;
  33 }
  34
  35 double AutoTuner::evaluateAll(SearchTuner *tuner) {
  36         double product = 1;
  37         for (uint i = 0; i < solvers.getSize(); i++) {
  38                 CSolver *problem = solvers.get(i);
  39                 double score = evaluate(problem, tuner);
  40                 product *= score;
  41         }
  42         return pow(product, 1 / ((double)solvers.getSize()));
  43 }
  44
  45 SearchTuner *AutoTuner::mutateTuner(SearchTuner *oldTuner, uint k) {
  46         SearchTuner *newTuner = oldTuner->copyUsed();
  47         uint numSettings = oldTuner->getSize();
  48         uint settingsToMutate = (uint)(AUTOTUNERFACTOR * (((double)numSettings) * (budget - k)) / (budget));
  49         if (settingsToMutate < 1)
  50                 settingsToMutate = 1;
  51         model_print("Mutating %u settings\n", settingsToMutate);
  52         while (settingsToMutate-- != 0) {
  53                 newTuner->randomMutate();
  54         }
  55         return newTuner;
  56 }
  57
  58
  59 void AutoTuner::tune() {
  60         SearchTuner *bestTuner = NULL;
  61         double bestScore = DBL_MAX;
  62
  63         SearchTuner *oldTuner = new SearchTuner();
  64         double base_temperature = evaluateAll(oldTuner);
  65         double oldScore = base_temperature;
  66
  67         for (uint i = 0; i < budget; i++) {
  68                 SearchTuner *newTuner = mutateTuner(oldTuner, i);
  69                 double newScore = evaluateAll(newTuner);
  70                 newTuner->printUsed();
  71                 model_print("Received score %f\n", newScore);
  72                 double scoreDiff = newScore - oldScore; //smaller is better
  73                 if (newScore < bestScore) {
  74                         if (bestTuner != NULL)
  75                                 delete bestTuner;
  76                         bestScore = newScore;
  77                         bestTuner = newTuner->copyUsed();
  78                 }
  79
  80                 double acceptanceP;
  81                 if (scoreDiff < 0) {
  82                         acceptanceP = 1;
  83                 } else {
  84                         double currTemp = base_temperature * (((double)budget - i) / budget);
  85                         acceptanceP = exp(-scoreDiff / currTemp);
  86                 }
  87                 double ran = ((double)random()) / RAND_MAX;
  88                 if (ran <= acceptanceP) {
  89                         delete oldTuner;
  90                         oldScore = newScore;
  91                         oldTuner = newTuner;
  92                 } else {
  93                         delete newTuner;
  94                 }
  95         }
  96         model_print("Best tuner:\n");
  97         bestTuner->print();
  98         bestTuner->serialize();
  99         model_print("Received score %f\n", bestScore);
 100         if (bestTuner != NULL)
 101                 delete bestTuner;
 102         delete oldTuner;
 103 }