public void TestMakeRandomTree()
{
var input1ParamExp = Expression.Parameter(typeof(int), "input1");
var input2ParamExp = Expression.Parameter(typeof(int), "input2");
var paramArr = new[] { input1ParamExp, input2ParamExp };
var random1 = Gp.MakeRandomTree(paramArr);
var printer = new GpPrinter();
TestOutput(printer.Display(random1));
var func = Expression.Lambda <Func <int, int, int> >(random1, paramArr).Compile();
TestOutput(func(7, 1));
TestOutput(func(2, 4));
var random2 = Gp.MakeRandomTree(paramArr);
TestOutput(printer.Display(random2));
var func2 = Expression.Lambda <Func <int, int, int> >(random2, paramArr).Compile();
TestOutput(func2(5, 3));
TestOutput(func2(5, 20));
}
public void TestExpressionTreeMutate()
{
var xParamExp = Expression.Parameter(typeof(int), "x");
var yParamExp = Expression.Parameter(typeof(int), "y");
var returnLabel = Expression.Label(typeof(int));
var blockExp = Expression.Block(
Expression.IfThenElse(
//if判断
Expression.GreaterThan(xParamExp, Expression.Constant(3)),
//if为true执行
Expression.Return(returnLabel, Expression.Add(yParamExp, Expression.Constant(5))),
//else执行
Expression.Return(returnLabel, Expression.Subtract(yParamExp, Expression.Constant(2)))
),
Expression.Label(returnLabel, Expression.Constant(0))
);
var printer = new GpPrinter();
TestOutput(printer.Display(blockExp));
var mutater = new ExpTestMutate();
var newExp = mutater.Mutate(blockExp);
TestOutput(printer.Display(newExp));
}
public void TestMutate()
{
var gp = new Gp();
var input1ParamExp = Expression.Parameter(typeof(int), "input1");
var input2ParamExp = Expression.Parameter(typeof(int), "input2");
var paramArr = new[] { input1ParamExp, input2ParamExp };
var random1 = Gp.MakeRandomTree(paramArr);
var printer = new GpPrinter();
TestOutput(printer.Display(random1));
TestOutput("-----------我是分隔线-------------");
var newExp = gp.Mutate(random1, paramArr);
TestOutput(printer.Display(newExp));
}
public void TestCrossOver()
{
var gp = new Gp();
var printer = new GpPrinter();
var input1ParamExp = Expression.Parameter(typeof(int), "input1");
var input2ParamExp = Expression.Parameter(typeof(int), "input2");
var paramArr = new[] { input1ParamExp, input2ParamExp };
var random1 = Gp.MakeRandomTree(paramArr);
TestOutput(printer.Display(random1));
TestOutput("-----------我是分隔线-------------");
var random2 = Gp.MakeRandomTree(paramArr);
TestOutput(printer.Display(random2));
TestOutput("-----------我是分隔线-------------");
var crossed = gp.CrossOver(random1, random2);
TestOutput(printer.Display(crossed));
}
public Func <int, int, int> Evolve(ParameterExpression[] pc, int popsize,
Func <List <ValueTuple <Func <int, int, int>, Expression> >, List <ValueTuple <long, Func <int, int, int>, Expression> > > rankfunction, int maxgen = 500, double mutationrate = 0.1,
double breedingreate = 0.4, double pexp = 0.7, double pnew = 0.05)
{
//返回一个随机数，通常是一个较小的数
//pexp的取值越小，我们得到的随机数就越小
Func <int> selectIndex = () => (int)(Math.Log(RndGenerator.RndDouble()) / Math.Log(pexp));
// 创建一个随机的初始种群
var population = new List <ValueTuple <Func <int, int, int>, Expression> >(popsize);
for (int i = 0; i < popsize; i++)
{
var exp = MakeRandomTree(pc);
var func = exp.Compile <Func <int, int, int> >(pc);
population.Add((func, exp));
}
List <ValueTuple <long, Func <int, int, int>, Expression> > scores = null;
for (int i = 0; i < maxgen; i++)
{
scores = rankfunction(population);
_outputWriter?.Invoke(scores[0].Item1);
if (scores[0].Item1 == 0)
{
break;
}
// 取两个最优的程序
var newpop = new List <ValueTuple <Func <int, int, int>, Expression> >()
{
(scores[0].Item2, scores[0].Item3),
(scores[1].Item2, scores[1].Item3)
};
//构造下一代
while (newpop.Count < popsize)
{
if (RndGenerator.RndDouble() > pnew)
{
var exp = Mutate(
CrossOver(scores[selectIndex()].Item3,
scores[selectIndex()].Item3, breedingreate), pc, mutationrate);
var func = exp.Compile <Func <int, int, int> >(pc);
newpop.Add((func, exp));
}
else
{
//加入一个随机节点，增加种群的多样性
var exp = MakeRandomTree(pc);
var func = exp.Compile <Func <int, int, int> >(pc);
newpop.Add((func, exp));
}
}
population = newpop;
}
var printer = new GpPrinter();
_outputWriter?.Invoke(printer.Display(scores[0].Item3));
return(scores[0].Item2);
}
