/// <summary>
/// Apply the resolution rule to passed clauses
/// </summary>
/// <param name="node1"></param>
/// <param name="node2"></param>
/// <returns>The list of formulas, which is a the logical consequence of input clauses</returns>
public static IEnumerable <INode> Resolve(INode node1, INode node2)
{
var rule = RulesLibrary.GetResolutionRule();
var instances = rule.SelectWhere(node1, node2);
return(instances.Select(ins => rule
.Apply(ins)
.Where(z => z.Children.Length > 0)
.ToArray())
.Select(nodes => nodes.Length == 1 ? nodes[0] : new MultipleOr(nodes))
.ToList());
}
/// <summary>
/// Calculate partial differentiation of function, represented as syntax tree
/// </summary>
/// <param name="node">Function tree</param>
/// <param name="index">Index of variable</param>
/// <param name="variable">Variable symbol</param>
/// <returns></returns>
public static INode Differentiate(INode node, int index = 0, String variable = "")
{
var varIndex = index;
var varName = NodeElementNames.GetVariableNodeNames().ElementAt(index);
var rules = RulesLibrary.GetSimplificationRules().ToList();
rules.AddRange(RulesLibrary.GetDifferentiationRules());
if (variable.Equals("") || NodeElementNames.GetVariableNodeNames().IndexOf(variable) == -1)
{
return(RulesLibrary.ApplyRules(new Dif <double>(node, VariableNode.Make <double>(varIndex, varName)), rules.ToArray()));
}
varIndex = NodeElementNames.GetVariableNodeNames().IndexOf(variable);
varName = variable;
return(RulesLibrary.ApplyRules(new Dif <double>(node, VariableNode.Make <double>(varIndex, varName)), rules.ToArray()));
}
/// <summary>
/// Simplify tree, using simplification rules from <see cref="RulesLibrary"/>
/// </summary>
/// <param name="tree"></param>
/// <returns></returns>
public static INode Simplify(INode tree)
{
return(RulesLibrary.ApplyRules(tree, RulesLibrary.GetSimplificationRules()));
}