简单的遗传算法源代码

2007年11月07日 14:56:00
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  文章由算法源码吧(www.sfcode.cn)收集
  这是一个非常简单的遗传算法源代码,是由Denis Cormier (North Carolina State University)开发的,Sita S.Raghavan (University of North Carolina at Charlotte)修正。代码保证尽可能少,实际上也不必查错。对一特定的应用修正此代码,用户只需改变常数的定义并且定义“评价函数”即可。注意代码 的设计是求最大值,其中的目标函数只能取正值;且函数值和个体的适应值之间没有区别。该系统使用比率选择、精华模型、单点杂交和均匀变异。如果用 Gaussian变异替换均匀变异,可能得到更好的效果。代码没有任何图形,甚至也没有屏幕输出,主要是保证在平台之间的高可移植性。读者可以从ftp.uncc.edu, 目录 coe/evol中的文件prog.c中获得。要求输入的文件应该命名为‘gadata.txt’;系统产生的输出文件为‘galog.txt’。输入的 文件由几行组成:数目对应于变量数。且每一行提供次序——对应于变量的上下界。如第一行为第一个变量提供上下界,第二行为第二个变量提供上下界,等等。
  
  
  
  
  
  
  #include
  #include
  #include
  
  #define POPSIZE 50
  #define MAXGENS 1000
  #define NVARS 3
  #define PXOVER 0.8
  #define PMUTATION 0.15
  #define TRUE 1
  #define FALSE 0
  int generation;
  int cur_best;
  FILE *galog;
  struct genotype
  {
  double gene[NVARS];
  double fitness;
  double upper[NVARS];
  double lower[NVARS];
  double rfitness;
  double cfitness;
  };
  struct genotype population[POPSIZE+1];
  struct genotype newpopulation[POPSIZE+1];
  
  
  
  void initialize(void);
  double randval(double, double);
  void evaluate(void);
  void keep_the_best(void);
  void elitist(void);
  void select(void);
  void crossover(void);
  void Xover(int,int);
  void swap(double *, double *);
  void mutate(void);
  void report(void);
  
  
  
  
  
  
  
  
  
  
  
  void initialize(void)
  {
  FILE *infile;
  int i, j;
  double lbound, ubound;
  if ((infile = fopen("gadata.txt","r"))==NULL)
  {
  fprintf(galog,"\nCannot open input file!\n");
  exit(1);
  }
  
  for (i = 0; i
  {
  fscanf(infile, "%lf",&lbound);
  fscanf(infile, "%lf",&ubound);
  for (j = 0; j
  {
  population[j].fitness = 0;
  population[j].rfitness = 0;
  population[j].cfitness = 0;
  population[j].lower[i] = lbound;
  population[j].upper[i]= ubound;
  population[j].gene[i] = randval(population[j].lower[i],
  population[j].upper[i]);
  }
  }
  fclose(infile);
  }
  
  
  
  double randval(double low, double high)
  {
  double val;
  val = ((double)(rand()%1000)/1000.0)*(high - low) + low;
  return(val);
  }
  
  
  
  
  
  void evaluate(void)
  {
  int mem;
  int i;
  double x[NVARS+1];
  for (mem = 0; mem
  {
  for (i = 0; i
  x[i+1] = population[mem].gene[i];
  population[mem].fitness = (x[1]*x[1]) - (x[1]*x[2]) + x[3];
  }
  }
  
  
  
  
  
  void keep_the_best()
  {
  int mem;
  int i;
  cur_best = 0;
  for (mem = 0; mem
  {
  if (population[mem].fitness >population[POPSIZE].fitness)
  {
  cur_best = mem;
  population[POPSIZE].fitness = population[mem].fitness;
  }
  }
  
  for (i = 0; i
  population[POPSIZE].gene[i] = population[cur_best].gene[i];
  }
  
  
  
  
  
  
  
  void elitist()
  {
  int i;
  double best, worst;
  int best_mem, worst_mem;
  best = population[0].fitness;
  worst = population[0].fitness;
  for (i = 0; i
  {
  if(population[i].fitness >population[i+1].fitness)
  {
  if (population[i].fitness >= best)
  {
  best = population[i].fitness;
  best_mem = i;
  }
  if (population[i+1].fitness <= worst)
  {
  worst = population[i+1].fitness;
  worst_mem = i + 1;
  }
  }
  else
  {
  if (population[i].fitness <= worst)
  {
  worst = population[i].fitness;
  worst_mem = i;
  }
  if (population[i+1].fitness >= best)
  {
  best = population[i+1].fitness;
  best_mem = i + 1;
  }
  }
  }
  
  
  
  
  
  if (best >= population[POPSIZE].fitness)
  {
  for (i = 0; i
  population[POPSIZE].gene[i] = population[best_mem].gene[i];
  population[POPSIZE].fitness = population[best_mem].fitness;
  }
  else
  {
  for (i = 0; i
  population[worst_mem].gene[i] = population[POPSIZE].gene[i];
  population[worst_mem].fitness = population[POPSIZE].fitness;
  }
  }
  
  
  
  
  
  void select(void)
  {
  int mem, i, j, k;
  double sum = 0;
  double p;
  
  for (mem = 0; mem
  {
  sum += population[mem].fitness;
  }
  
  for (mem = 0; mem
  {
  population[mem].rfitness = population[mem].fitness/sum;
  }
  population[0].cfitness = population[0].rfitness;
  
  for (mem = 1; mem
  {
  population[mem].cfitness = population[mem-1].cfitness +
  population[mem].rfitness;
  }
  
  for (i = 0; i
  {
  p = rand()%1000/1000.0;
  if (p
  newpopulation[i] = population[0];
  else
  {
  for (j = 0; j
  if (p >= population[j].cfitness &&
  p
  newpopulation[i] = population[j+1];
  }
  }
  
  for (i = 0; i
  population[i] = newpopulation[i];
  }
  
  
  
  
  void crossover(void)
  {
  int i, mem, one;
  int first = 0;
  double x;
  for (mem = 0; mem
  {
  x = rand()%1000/1000.0;
  if (x
  {
  ++first;
  if (first % 2 == 0)
  Xover(one, mem);
  else
  one = mem;
  }
  }
  }
  
  
  
  void Xover(int one, int two)
  {
  int i;
  int point;
  
  if(NVARS >1)
  {
  if(NVARS == 2)
  point = 1;
  else
  point = (rand() % (NVARS - 1)) + 1;
  for (i = 0; i
  swap(&population[one].gene[i], &population[two].gene[i]);
  }
  }
  
  
  
  void swap(double *x, double *y)
  {
  double temp;
  temp = *x;
  *x = *y;
  *y = temp;
  }
  
  
  
  
  
  void mutate(void)
  {
  int i, j;
  double lbound, hbound;
  double x;
  for (i = 0; i
  for (j = 0; j
  {
  x = rand()%1000/1000.0;
  if (x
  {
  
  lbound = population[i].lower[j];
  hbound = population[i].upper[j];
  population[i].gene[j] = randval(lbound, hbound);
  }
  }
  }
  
  
  
  
  void report(void)
  {
  int i;
  double best_val;
  double avg;
  double stddev;
  double sum_square;
  double square_sum;
  double sum;
  sum = 0.0;
  sum_square = 0.0;
  for (i = 0; i
  {
  sum += population[i].fitness;
  sum_square += population[i].fitness * population[i].fitness;
  }
  avg = sum/(double)POPSIZE;
  square_sum = avg * avg * POPSIZE;
  stddev = sqrt((sum_square - square_sum)/(POPSIZE - 1));
  best_val = population[POPSIZE].fitness;
  fprintf(galog, "\n%5d, %6.3f, %6.3f, %6.3f \n\n", generation,
  best_val, avg, stddev);
  }
  
  
  
  
  
  
  void main(void)
  {
  int i;
  if ((galog = fopen("galog.txt","w"))==NULL)
  {
  exit(1);
  }
  generation = 0;
  fprintf(galog, "\n generation best average standard \n");
  fprintf(galog, " number value fitness deviation \n");
  initialize();
  evaluate();
  keep_the_best();
  while(generation
  {
  generation++;
  select();
  crossover();
  mutate();
  report();
  evaluate();
  elitist();
  }
  fprintf(galog,"\n\n Simulation completed\n");
  fprintf(galog,"\n Best member: \n");
  for (i = 0; i
  {
  fprintf (galog,"\n var(%d) = %3.3f",i,population[POPSIZE].gene[i]);
  }
  fprintf(galog,"\n\n Best fitness = %3.3f",population[POPSIZE].fitness);
  fclose(galog);
  printf("Success\n");
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原文地址:https://www.cnblogs.com/feisky/p/1586624.html