我试图生成具有一些限制的半随机子集。子集的半随机集
下面是与示例值的变量的描述:
- ObjCount - 对象的数量(12)
- VisibleCount(AKA的setSize) - 每组对象的数量(6)
- SetCount - 组(12)
- ObjAppearances数量 - 在其中出现的对象组的数量=
SetCount * VisibleCount/ObjCount
我需要制作一个给定的多套(SetCount),其遵循以下规则:
- 每一组是对象的集合,但没有对象可以是在一组不止一次。
- 此外,每个对象应该在相同数量的集合中。 如果它不均匀分布,那么一个对象出现的数字集可以被关闭1(一些对象在4个集合中,另外一些在5中)。我会尽量避免这种情况,所以这不是关键。
事实证明,这并不像我最初想象的那么微不足道。任何人都可以帮我一些代码/ psuedocode?一个通用版本的解决方案也是非常有用的。
在此先感谢。
编辑: VisibleCount是设定的大小。对象出现的次数(ObjAppearances)为SetCount * VisibleCount/ObjCount
编辑2:我还应该补充说我希望这些集合相当随机。如果这些集合都具有顺序对象(例如set1:5,6,7 set2:3,4,5 set3:10,11,0),则该解决方案无用。对不起,没有说清楚。
编辑3:这是一个不起作用的解决方案。 (在C#)
static void Main(string[] args)
{
var ObjectCount = 12;
var SetSize = 6;
var SetCount = 12;
var Sets = Enumerable.Range(0, SetCount).Select(i => new List<int>()).ToArray(); // a SetCount-sized array of lists
var ObjectAppearances = SetSize * SetCount/ObjectCount;
var rand = new Random();
// fill the sets
for (int obj = 0; obj < ObjectCount; obj++)
{
for (int a = 0; a < ObjectAppearances; a++)
{
// get the collection of sets that are not full
var nonFullSets = Sets.Where(s => s.Count < SetSize);
// get the collection of non-full sets without obj
var setsWithoutObj = nonFullSets.Where(s => !s.Contains(obj));
///////////////////////
// Here is the problem. All of the non-full sets may already
// have a copy of obj
///////////////////////
// choose a set at random
var currentSetIndex = rand.Next(setsWithoutObj.Count());
var currentSet = setsWithoutObj.ElementAt(currentSetIndex);
// add the object
currentSet.Add(obj);
}
}
// randomize the order within each set and output each
for (int i = 0; i < SetCount; i++)
{
var randomlyOrderedSet = Sets[i].OrderBy(obj => rand.Next());
Sets[i] = new List<int>(randomlyOrderedSet);
// output
foreach (var obj in Sets[i])
Console.Write(string.Format("{0}, ", obj));
Console.WriteLine();
}
Console.ReadLine();
}
这里的解决方案 - MizardX的答案的实现
static void Main(string[] args)
{
var ObjectCount = 12;
var SetSize = 6;
var SetCount = 10;
var rand = new Random();
// make a matrix [SetCount][ObjectCount]
var Matrix = new int[SetCount][];
for (int s = 0; s < SetCount; s++)
Matrix[s] = Enumerable.Repeat(0, ObjectCount).ToArray();
// put approximately the same number of objects in each set by
// adding sequential objects to sequential sets (not random)
for (int s = 0; s < SetCount; s++)
{
var firstObject = (int)Math.Ceiling((double)s * ObjectCount/SetCount);
for (int i = 0; i < SetSize; i++)
{
var o = (firstObject + i) % ObjectCount;
Matrix[s][o] = 1;
}
}
// output the result
for (int s = 0; s < SetCount; s++)
{
for (int o = 0; o < ObjectCount; o++)
{
Console.Write(string.Format("{0}, ", Matrix[s][o]));
}
Console.WriteLine();
}
Console.WriteLine();
// shuffle sets
Matrix = Matrix.OrderBy(s => rand.Next()).ToArray();
// make a new matrix for shuffle objects
var objOrder = Enumerable.Range(0, ObjectCount).OrderBy(o => rand.Next()).ToArray();
var MatrixSuffled = new int[SetCount][];
for (int s = 0; s < SetCount; s++)
MatrixSuffled[s] = Enumerable.Repeat(0, ObjectCount).ToArray();
for (int o = 0; o < ObjectCount; o++)
{
var oldObj = o;
var newObj = objOrder[o];
for (int s = 0; s < SetCount; s++)
{
MatrixSuffled[s][newObj] = Matrix[s][oldObj];
}
}
// check and output the result
var objectCounters = Enumerable.Repeat(0, ObjectCount).ToArray();
for (int s = 0; s < SetCount; s++)
{
var objectsInThisSet = 0;
for (int o = 0; o < ObjectCount; o++)
{
objectsInThisSet += MatrixSuffled[s][o];
objectCounters[o] += MatrixSuffled[s][o];
Console.Write(string.Format("{0}, ", MatrixSuffled[s][o]));
}
Console.Write(string.Format(" {0}", objectsInThisSet));
Console.WriteLine();
}
// output object count
Console.WriteLine();
for (int o = 0; o < ObjectCount; o++)
Console.Write(string.Format("{0} ", objectCounters[o]));
Console.ReadLine();
}
感谢您的帮助,但请参阅edit2。 – sharoz 2011-02-27 03:51:08
只有你可以在约束条件下获得很多不同的集合。如果你绝对不想要一个序列,你可以重复这个算法,直到你得到满意的结果。 – 2011-02-27 04:10:56
我明白了。我会尽力实施并让你知道很快... – sharoz 2011-02-27 04:33:46