/// <summary>
/// foamliu, 2009/01/19, 扩展规划图.
///
/// Expand the planning graph, one action layer and one proposition layer at a time.
///
/// </summary>
private bool ExpandGraph()
{
for (int i = 1; i <= MaxLevel; i++)
{
// 创建 Ai 和 Pi+1
List <Action> actions = this.m_operators.GenActions(this.m_lastProp.Conjunction);
ActionLayer aLayer = new ActionLayer(this.m_lastProp, actions);
aLayer.Number = this.m_lastProp.Number;
this.m_lastProp.NextLayer = aLayer;
this.m_lastProp = aLayer.NextLayer;
this.m_lastProp.Number = aLayer.Number + 1;
if (GoalsReachable())
{
return(true);
}
// 测试是否 Level Off
if (LevelOff())
{
System.Console.WriteLine("Graph Levels Off at level" + m_lastProp.Number);
return(false);
}
}
System.Console.WriteLine("到达了预设的最大 Level:" + MaxLevel);
return(false);
}
/// <summary>
/// foamliu, 2009/01/19, 初始化规划图.
/// </summary>
private void InitGraph()
{
// 初始条件构成第一个命题层: P1.
this.m_firstProp = new PropositionLayer();
this.m_firstProp.SetInitLayer(this.m_initials);
// 参见类头注释.
this.m_firstProp.Number = 1;
this.m_lastProp = this.m_firstProp;
}
/// <summary>
/// foamliu, 2009/01/19.
///
/// 如果一直找不到有效的规划, 则最后会到达一个命题层 P, 之后所有的命题层都与它完全相同.
/// 原因: 由于 No-Op actions 的存在, 一个命题出现在某个命题层中, 则它也必然出现在后续的命题层中.
/// 也就是命题层中命题数量是单调递增的, 而在命题有限的情况下又是有界的, 所以必然会有最大值.
///
/// 这个条件可以作为图扩展的结束测试.
/// </summary>
/// <returns></returns>
private bool LevelOff()
{
PropositionLayer p = this.m_lastProp;
ActionLayer act = p.PrevLayer;
if (!p.Equals(act.PrevLayer))
{
return(false);
}
return(true);
}
/// <summary>
/// foamliu, 2009/01/22, for debug use.
/// </summary>
/// <returns></returns>
public override string ToString()
{
StringBuilder sb = new StringBuilder();
PropositionLayer pLayer = m_firstProp;
ActionLayer aLayer;
while (pLayer != null)
{
sb.Append(pLayer.ToString());
aLayer = pLayer.NextLayer;
if (aLayer != null)
{
sb.Append(aLayer.ToString());
pLayer = aLayer.NextLayer;
}
else
{
pLayer = null;
}
}
return(sb.ToString());
}
//public ActionLayer()
//{
//}
/// <summary>
/// foamliu, 2009/01/21.
/// </summary>
/// <param name="prev"></param>
/// <param name="acts"></param>
public ActionLayer(PropositionLayer prev, List <Action> acts)
{
this.m_actions = new List <Action>();
this.m_selectedActions = new List <Action>();
this.m_goalSet = new List <Goal>();
this.m_prev = prev;
this.m_next = new PropositionLayer(this);
foreach (Action act in acts)
{
this.m_actions.Add(act);
CreatePreEdges(act);
CreateAddEdges(act);
CreateDelEdges(act);
}
// add no-ops
AddNoops();
// 检测互斥的行为
TestMutex();
// 下一层检测互斥的命题
m_next.TestMutex();
}
