private Alpha_Memory BuildOrShareAlphaMemory(Condition c)
{
Constant_Test_Node current_node = this.m_top_node_of_alpha_network;
for (int j = 0; j < ReteInferenceEngine.WME_FIELD_NUM; j++)
{
// for each constant tests in each field of c
if (!(c.Fields[j] is Variable))
{
Term sym = c.Fields[j];
FieldType f = (FieldType)j;
current_node = BuildOrShareConstantTestNode(current_node, f, sym);
}
}
if (current_node.Output_Memory != null)
{
return(current_node.Output_Memory);
}
Alpha_Memory am = new Alpha_Memory();
current_node.Output_Memory = am;
am.Successors.Clear();
am.Items.Clear();
// initialize am with any current WMEs
foreach (WME w in this.m_workingmemory)
{
if (c.PassAllConstantTests(w))
{
AlphaMemoryActivation(am, w);
}
}
return(am);
}
public ReteInferenceEngine()
{
this.m_top_node_of_alpha_network = new Constant_Test_Node();
this.m_top_node_of_alpha_network.Field_To_Test = FieldType.No_Test;
this.m_dummy_top_node = new Dummy_Top_Node();
// just so there will be one thing to iterate over in the join-node-right-activation procedure.
this.m_workingmemory = new List <WME>();
// foamliu, 2008/11/21, remove "P_Nodes", access p-nodes from productions.
//
//this.m_p_nodes = new List<P_Node>();
}
private Constant_Test_Node BuildOrShareConstantTestNode(Constant_Test_Node parent, FieldType field, Term term)
{
// look for an existing node we can share
foreach (Constant_Test_Node child in parent.Children)
{
if (child.Field_To_Test == field && child.Thing_The_Field_Must_Equal.Equals(term))
{
return(child);
}
}
// couldn't find a node to share, so build a new one
Constant_Test_Node _new = new Constant_Test_Node();
parent.Children.Add(_new);
_new.Field_To_Test = field;
_new.Thing_The_Field_Must_Equal = term;
_new.Output_Memory = null;
_new.Children.Clear();
return(_new);
}
// assumes all tests are tests for equality with some constant symbol.
public void ConstantTestNodeActivation(Constant_Test_Node node, WME w)
{
if (node.Field_To_Test != FieldType.No_Test)
{
Term v = w.Fields[(int)node.Field_To_Test];
if (!v.Equals(node.Thing_The_Field_Must_Equal))
{
// failed the test, so don't propagate any further
return;
}
}
if (node.Output_Memory != null)
{
AlphaMemoryActivation(node.Output_Memory, w);
}
foreach (Constant_Test_Node c in node.Children)
{
ConstantTestNodeActivation(c, w);
}
}
