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->startEncoding();
  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) * 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 }