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 5000
  10 AutoTuner::AutoTuner(uint _budget) :
  11         budget(_budget), result(UNSETVALUE) {
  12 }
  13
  14 AutoTuner::~AutoTuner() {}
  15
  16 void AutoTuner::addProblem(CSolver *solver) {
  17         solvers.push(solver);
  18 }
  19
  20 long long AutoTuner::evaluate(CSolver *problem, SearchTuner *tuner) {
  21         CSolver *copy = problem->clone();
  22         copy->setTuner(tuner);
  23         copy->setSatSolverTimeout(TIMEOUTSEC);
  24         model_print("**********************\n");
  25         int sat = copy->solve();
  26         if (result == UNSETVALUE && sat != IS_INDETER)
  27                 result = sat;
  28         else if (result != sat && sat != IS_INDETER) {
  29                 model_print("&&&&&&&&&&&&&&&&&& Result has changed &&&&&&&&&&&&&\n");
  30                 copy->printConstraints();
  31         }
  32         long long metric = copy->getElapsedTime();
  33         delete copy;
  34         return metric;
  35 }
  36
  37 double AutoTuner::evaluateAll(SearchTuner *tuner) {
  38         double product = 1;
  39         for (uint i = 0; i < solvers.getSize(); i++) {
  40                 CSolver *problem = solvers.get(i);
  41                 double score = evaluate(problem, tuner);
  42                 product *= score;
  43         }
  44         return pow(product, 1 / ((double)solvers.getSize()));
  45 }
  46
  47 SearchTuner *AutoTuner::mutateTuner(SearchTuner *oldTuner, uint k) {
  48         SearchTuner *newTuner = oldTuner->copyUsed();
  49         uint numSettings = oldTuner->getSize();
  50         uint settingsToMutate = (uint)(AUTOTUNERFACTOR * (((double)numSettings) * (budget - k)) / (budget));
  51         if (settingsToMutate < 1)
  52                 settingsToMutate = 1;
  53         model_print("Mutating %u settings\n", settingsToMutate);
  54         while (settingsToMutate-- != 0) {
  55                 newTuner->randomMutate();
  56         }
  57         return newTuner;
  58 }
  59
  60 void AutoTuner::tune() {
  61         SearchTuner *bestTuner = NULL;
  62         double bestScore = DBL_MAX;
  63
  64         SearchTuner *oldTuner = new SearchTuner();
  65         double base_temperature = evaluateAll(oldTuner);
  66         double oldScore = base_temperature;
  67
  68         for (uint i = 0; i < budget; i++) {
  69                 SearchTuner *newTuner = mutateTuner(oldTuner, i);
  70                 double newScore = evaluateAll(newTuner);
  71                 newTuner->printUsed();
  72                 model_print("Received score %f\n", newScore);
  73                 double scoreDiff = newScore - oldScore; //smaller is better
  74                 if (newScore < bestScore) {
  75                         if (bestTuner != NULL)
  76                                 delete bestTuner;
  77                         bestScore = newScore;
  78                         bestTuner = newTuner->copyUsed();
  79                 }
  80
  81                 double acceptanceP;
  82                 if (scoreDiff < 0) {
  83                         acceptanceP = 1;
  84                 } else {
  85                         double currTemp = base_temperature * (((double)budget - i) / budget);
  86                         acceptanceP = exp(-scoreDiff / currTemp);
  87                 }
  88                 double ran = ((double)random()) / RAND_MAX;
  89                 if (ran <= acceptanceP) {
  90                         delete oldTuner;
  91                         oldScore = newScore;
  92                         oldTuner = newTuner;
  93                 } else {
  94                         delete newTuner;
  95                 }
  96         }
  97         model_print("Best tuner:\n");
  98         bestTuner->print();
  99         bestTuner->serialize("TUNER.conf");
 100         model_print("Received score %f\n", bestScore);
 101         if (bestTuner != NULL)
 102                 delete bestTuner;
 103         delete oldTuner;
 104 }