// Genetic Algorithm for nonlinear programming
// Written by Microsoft Visual C++
#include <stdio.h>
#include <stdlib.h>
#include <math.h>
static void initialization(void);
static void evaluation(int gen);
static void selection(void);
static void crossover(void);
static void mutation(void);
static void objective_function(void);
static int constraint_check(double x[]);
//取a,b间的随机数
double myu(double a, double b);
//变量个数
#define N 3 // number of variables
//目标函数个数
#define M 1 // number of objectives
#define TYPE 1 // 1=max;-1=min
#define GEN 400 // maximum generation number
//群体种群个数
#define POP_SIZE 30
//变异概率
#define P_MUTATION 0.2
//交叉概率
#define P_CROSSOVER 0.3
//染色体
double CHROMOSOME[POP_SIZE+1][N+1];
//保留目标函数值,OBJECTIVE[0][i]为最优值
double OBJECTIVE[POP_SIZE+1][M+1];
//基于排序的适应函数线性加速,q[0]为被选取的概率最大,与目标函数值无关
double q[POP_SIZE+1];
//计算目标函数值,放入OBJECTIVE[i][0],OBJECTIVE[i][1]
static void objective_function(void)
{
double x1,x2,x3;
int i;
for(i = 1; i <= POP_SIZE; i++) {
x1 = CHROMOSOME[i][1];
x2 = CHROMOSOME[i][2];
x3 = CHROMOSOME[i][3];
OBJECTIVE[i][1] = sqrt(x1)+sqrt(x2)+sqrt(x3);
}
for(i=1;i<=POP_SIZE;i++)
OBJECTIVE[i][0]= OBJECTIVE[i][1];
}
static int constraint_check(double x[])
{
double a;
int n;
for(n=1;n<=N;n++) if(x[n]<0) return 0;
a = x[1]*x[1]+2*x[2]*x[2]+3*x[3]*x[3];
if(a>1) return 0;
return 1;
}
static void initialization(void)
{
double x[N+1]; // N is the number of variables
int i,j;
for(i=1; i<=POP_SIZE; i++){
mark:
for(j=1; j<=N; j++) x[j]=myu(0,1);
if(constraint_check(x)==0) goto mark;
for(j=1; j<=N; j++) CHROMOSOME[i][j]=x[j];
}
}
main()
{
int i, j;
double a;
q[0]=0.05; a=0.05;
for(i=1; i<=POP_SIZE; i++) {a=a*0.95; q[i]=q[i-1]+a;}
initialization();
evaluation(0);
for(i=1; i<=GEN; i++) {
selection();
crossover();
mutation();
evaluation(i);
printf("\nGeneration NO.%d\n", i);
printf("x=(");
for(j=1; j<=N; j++) {
if(j<N) printf("%3.4f,",CHROMOSOME[0][j]);
else printf("%3.4f",CHROMOSOME[0][j]);
}
if(M==1) printf(")\nf=%3.4f\n", OBJECTIVE[0][1]);
else {
printf(")\nf=(");
for(j=1; j<=M; j++) {
if(j<M) printf("%3.4f,", OBJECTIVE[0][j]);
else printf("%3.4f", OBJECTIVE[0][j]);
}
printf(") Aggregating Value=%3.4f\n",OBJECTIVE[0][0]);
}
}
printf("\n");
return 1;
}
//根据目标函数值对染色体排序
static void evaluation(int gen)
{
double a;
int i, j, k, label;
objective_function();
if(gen==0){
for(k=0; k<=M; k++) OBJECTIVE[0][k]=OBJECTIVE[1][k];
for(j = 1; j <= N; j++) CHROMOSOME[0][j]=CHROMOSOME[1][j];
}
for(i=0; i<POP_SIZE; i++){
label=0; a=OBJECTIVE[i][0];
for(j=i+1; j<=POP_SIZE; j++)
if((TYPE*a)<(TYPE*OBJECTIVE[j][0])) {
a=OBJECTIVE[j][0];
label=j;
}
if(label!=0) {
for(k=0; k<=M; k++) {
a=OBJECTIVE[i][k];
OBJECTIVE[i][k]=OBJECTIVE[label][k];
OBJECTIVE[label][k]=a;
}
for(j=1; j<=N; j++) {
a=CHROMOSOME[i][j];
CHROMOSOME[i][j]=CHROMOSOME[label][j];
CHROMOSOME[label][j]=a;
}
}
}
}
static void selection()
{
double r, temp[POP_SIZE+1][N+1];
int i, j, k;
for(i=1; i<=POP_SIZE; i++) {
r=myu(0, q[POP_SIZE]);
for(j=0; j<=POP_SIZE; j++) {
if(r<=q[j]) {
for(k=1; k<=N; k++) temp[i][k]=CHROMOSOME[j][k];
break;
}
}
}
for(i=1; i<=POP_SIZE; i++)
for(k=1; k<=N; k++)
CHROMOSOME[i][k]=temp[i][k];
}
//交叉算法
//以交叉概率随机选取两个染色体进行交叉,分别取r和1-r加权和
static void crossover()
{
int i, j, jj, k, pop;
double r, x[N+1], y[N+1];
pop=POP_SIZE/2;//因为一次产生两个,所以循环一半次
for(i=1; i<=pop; i++) {
if(myu(0,1)>P_CROSSOVER) continue;
j=(int)myu(1,POP_SIZE);
jj=(int)myu(1,POP_SIZE);
r=myu(0,1);
//一次产生两个新的染色体
for(k=1; k<=N; k++) {
x[k]=r*CHROMOSOME[j][k]+(1-r)*CHROMOSOME[jj][k];
y[k]=r*CHROMOSOME[jj][k]+(1-r)*CHROMOSOME[j][k];
}
if(constraint_check(x)==1)
for(k=1; k<=N; k++) CHROMOSOME[j][k]=x[k];
if(constraint_check(y)==1)
for(k=1; k<=N; k++) CHROMOSOME[jj][k]=y[k];
}
}
static void mutation(void)
{
int i, j, k;
double x[N+1], y[N+1], infty, direction[N+1];
double INFTY=10, precision=0.0001;
for(i=1; i<=POP_SIZE; i++) {
if(myu(0,1)>P_MUTATION) continue;
//每个分量一个随机方向
for(k=1; k<=N; k++) x[k] = CHROMOSOME[i][k];
for(k=1; k<=N; k++)
if(myu(0,1)<0.5) direction[k]=myu(-1,1);
else direction[k]=0;
infty=myu(0,INFTY);
while(infty>precision) {
for(j=1; j<=N; j++) y[j]=x[j]+infty*direction[j];
if(constraint_check(y)==1) {
//第i个染色体发生变异
for(k=1; k<=N; k++) CHROMOSOME[i][k]=y[k];
break;
}
infty=myu(0,infty);
}
}
}
static double myu(double a, double b) // Uniform Distribution
{
double y;
if(a>b) {
printf("\nThe first parameter should be less than the second!");
exit(1);
}
y = (double)rand()/(RAND_MAX);
return (a+(b-a)*y);
}