C#实现遗传算法，模拟花朵的进化
文/gpcuster 出处/博客园
以下代码实现了一个简单的花朵进化的模拟过程。
花朵的种群数量是10，共进化了50代。
通过运行程序，你会发现通过不断的进化，种群的总的适应环境的能力在逐步提高（fitness的值下降）。
实现代码：
using System;
using System.Collections.Generic;
using System.Text;
namespace GA
{
class Program
{
static void Main(string[] args)
{
World world = new World();
world.Init();
for (int i = 0; i < 50; i++)
{
world.Evolve();
Console.WriteLine(i);
world.Show();
}
}
}
class World
{
int kMaxFlowers = 11;
Random Rnd = new Random();
public int[] temperature;
public int[] water;
public int[] sunlight;
public int[] nutrient;
public int[] beneficialInsect;
public int[] harmfulInsect;
public int currentTemperature;
public int currentWater;
public int currentSunlight;
public int currentNutrient;
public int currentBeneficialInsect;
public int currentHarmfulInsect;
public World()
{
temperature = new int[kMaxFlowers];
water = new int[kMaxFlowers];
sunlight = new int[kMaxFlowers];
nutrient = new int[kMaxFlowers];
beneficialInsect = new int[kMaxFlowers];
harmfulInsect = new int[kMaxFlowers];
}
/**//// <summary>
/// 初始化第一代花朵的基因结构
/// </summary>
public void Init()
{
for (int i = 1; i < kMaxFlowers; i++)
{
temperature
= Rnd.Next(1, 75);
water = Rnd.Next(1, 75);
sunlight = Rnd.Next(1, 75);
nutrient = Rnd.Next(1, 75);
beneficialInsect = Rnd.Next(1, 75);
harmfulInsect = Rnd.Next(1, 75);
}
currentTemperature = Rnd.Next(1, 75);
currentWater = Rnd.Next(1, 75);
currentSunlight = Rnd.Next(1, 75);
currentNutrient = Rnd.Next(1, 75);
currentBeneficialInsect = Rnd.Next(1, 75);
currentHarmfulInsect = Rnd.Next(1, 75);
}
/**//// <summary>
/// 越大说明花朵的适应环境的能力差，小说明适应环境的能力强
/// </summary>
/// <param name="flower"></param>
/// <returns></returns>
private int Fitness(int flower)
{
int theFitness = 0;
theFitness = Math.Abs(temperature[flower] - currentTemperature);
theFitness = theFitness + Math.Abs(water[flower] - currentWater);
theFitness = theFitness + Math.Abs(sunlight[flower] -
currentSunlight);
theFitness = theFitness + Math.Abs(nutrient[flower] -
currentNutrient);
theFitness = theFitness + Math.Abs(beneficialInsect[flower] -
currentBeneficialInsect);
theFitness = theFitness + Math.Abs(harmfulInsect[flower] -
currentHarmfulInsect);
return (theFitness);
}
/**//// <summary>
/// 排除适应能力差的花朵，让适应能力强的花朵杂交繁殖，产生下一代。同时有一定的概率变异。
/// </summary>
public void Evolve()
{
int[] fitTemperature = new int[kMaxFlowers];
int[] fitWater = new int[kMaxFlowers];
int[] fitSunlight = new int[kMaxFlowers];
int[] fitNutrient = new int[kMaxFlowers];
int[] fitBeneficialInsect = new int[kMaxFlowers];
int[] fitHarmfulInsect = new int[kMaxFlowers];
int[] fitness = new int[kMaxFlowers];
int i;
int leastFit = 0;
int leastFitIndex = 1;
for (i = 1; i < kMaxFlowers; i++)
if (Fitness(i) > leastFit)
{
leastFit = Fitness(i);
leastFitIndex = i;
}
temperature[leastFitIndex] = temperature[Rnd.Next(1, 10)];
water[leastFitIndex] = water[Rnd.Next(1, 10)];
sunlight[leastFitIndex] = sunlight[Rnd.Next(1, 10)];
nutrient[leastFitIndex] = nutrient[Rnd.Next(1, 10)];
beneficialInsect[leastFitIndex] = beneficialInsect[Rnd.Next(1, 10)];
harmfulInsect[leastFitIndex] = harmfulInsect[Rnd.Next(1, 10)];
for (i = 1; i < kMaxFlowers; i++)
{
fitTemperature = temperature[Rnd.Next(1, 10)];
fitWater = water[Rnd.Next(1, 10)];
fitSunlight = sunlight[Rnd.Next(1, 10)];
fitNutrient = nutrient[Rnd.Next(1, 10)];
fitBeneficialInsect = beneficialInsect[Rnd.Next(1, 10)];
fitHarmfulInsect = harmfulInsect[Rnd.Next(1, 10)];
}
for (i = 1; i < kMaxFlowers; i++)
{
temperature = fitTemperature;
water = fitWater;
sunlight = fitSunlight;
nutrient = fitNutrient;
beneficialInsect = fitBeneficialInsect;
harmfulInsect = fitHarmfulInsect;
}
for (i = 1; i < kMaxFlowers; i++)
{
if (Rnd.Next(1, 100) == 1)
temperature = Rnd.Next(1, 75);
if (Rnd.Next(1, 100) == 1)
water = Rnd.Next(1, 75);
if (Rnd.Next(1, 100) == 1)
sunlight = Rnd.Next(1, 75);
if (Rnd.Next(1, 100) == 1)
nutrient = Rnd.Next(1, 75);
if (Rnd.Next(1, 100) == 1)
beneficialInsect = Rnd.Next(1, 75);
if (Rnd.Next(1, 100) == 1)
harmfulInsect = Rnd.Next(1, 75);
}
}
/**//// <summary>
/// 显示种群中个体对环境的适应能力，还有所有个体对环境的适应能力之和。
/// </summary>
public void Show()
{
int sum = 0;
for (int i = 1; i < kMaxFlowers; i++)
{
int fitness = Fitness(i);
sum += fitness;
Console.WriteLine("No." + i + "'s fitness is " + fitness);
}
Console.WriteLine("fitness sum is " + sum);
}
}
}
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