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
  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         model_print("**********************\n");
  22         int sat = copy->solve();
  23         if (result == UNSETVALUE)
  24                 result = sat;
  25         else if (result != sat) {
  26                 model_print("&&&&&&&&&&&&&&&&&& Result has changed &&&&&&&&&&&&&\n");
  27                 copy->printConstraints();
  28         }
  29         //model_print("SAT %d\n", result);
  30         long long elapsedTime = copy->getElapsedTime();
  31 //      long long encodeTime = copy->getEncodeTime();
  32 //      long long solveTime = copy->getSolveTime();
  33         long long metric = elapsedTime;
  34 //      model_print("Elapsed Time: %llu\n", elapsedTime);
  35 //      model_print("Encode Time: %llu\n", encodeTime);
  36 //      model_print("Solve Time: %llu\n", solveTime);
  37         delete copy;
  38         return metric;
  39 }
  40
  41 double AutoTuner::evaluateAll(SearchTuner *tuner) {
  42         double product = 1;
  43         for (uint i = 0; i < solvers.getSize(); i++) {
  44                 CSolver *problem = solvers.get(i);
  45                 double score = evaluate(problem, tuner);
  46                 product *= score;
  47         }
  48         return pow(product, 1 / ((double)solvers.getSize()));
  49 }
  50
  51 SearchTuner *AutoTuner::mutateTuner(SearchTuner *oldTuner, uint k) {
  52         SearchTuner *newTuner = oldTuner->copyUsed();
  53         uint numSettings = oldTuner->getSize();
  54         double factor = 0.3;//Adjust this factor...
  55         uint settingsToMutate = (uint)(factor * (((double)numSettings) * (budget - k)) / (budget));
  56         if (settingsToMutate < 1)
  57                 settingsToMutate = 1;
  58         model_print("Mutating %u settings\n", settingsToMutate);
  59         while (settingsToMutate-- != 0) {
  60                 newTuner->randomMutate();
  61         }
  62         return newTuner;
  63 }
  64
  65
  66 void AutoTuner::tune() {
  67         SearchTuner *bestTuner = NULL;
  68         double bestScore = DBL_MAX;
  69
  70         SearchTuner *oldTuner = new SearchTuner();
  71         double base_temperature = evaluateAll(oldTuner);
  72         double oldScore = base_temperature;
  73
  74         for (uint i = 0; i < budget; i++) {
  75                 SearchTuner *newTuner = mutateTuner(oldTuner, i);
  76                 double newScore = evaluateAll(newTuner);
  77                 newTuner->printUsed();
  78                 model_print("Received score %f\n", newScore);
  79                 double scoreDiff = newScore - oldScore; //smaller is better
  80                 if (newScore < bestScore) {
  81                         if (bestTuner != NULL)
  82                                 delete bestTuner;
  83                         bestScore = newScore;
  84                         bestTuner = newTuner->copyUsed();
  85                 }
  86
  87                 double acceptanceP;
  88                 if (scoreDiff < 0) {
  89                         acceptanceP = 1;
  90                 } else {
  91                         double currTemp = base_temperature * (((double)budget - i) / budget);
  92                         acceptanceP = exp(-scoreDiff / currTemp);
  93                 }
  94                 double ran = ((double)random()) / RAND_MAX;
  95                 if (ran <= acceptanceP) {
  96                         delete oldTuner;
  97                         oldScore = newScore;
  98                         oldTuner = newTuner;
  99                 } else {
 100                         delete newTuner;
 101                 }
 102         }
 103         model_print("Best tuner:\n");
 104         bestTuner->print();
 105         bestTuner->serialize();
 106         model_print("Received score %f\n", bestScore);
 107         if (bestTuner != NULL)
 108                 delete bestTuner;
 109         delete oldTuner;
 110 }