public override double EvaluateVarFunction(VarFuncToken token)
{
Func <double, double> func;
int start;
switch (token.Symbol)
{
case ParserSymbols.Sum:
func = ExpressionTreeEvaluator.CreateDelegate(token.SubTokens[3],
token.VariableSymbol, parser, Context.Options);
start = (int)eval(token.SubTokens[1]);
return(Enumerable.Range(start, (int)eval(token.SubTokens[2]) - start + 1)
.Select(v => func(v)).Sum());
case ParserSymbols.Prod:
func = ExpressionTreeEvaluator.CreateDelegate(token.SubTokens[3],
token.VariableSymbol, parser, Context.Options);
start = (int)eval(token.SubTokens[1]);
return(Enumerable.Range(start, (int)eval(token.SubTokens[2]) - start + 1)
.Select(v => func(v))
.Aggregate((v1, v2) => v1 * v2));
default:
if (Context.Options.StrictMode)
{
throw new UnsupportedOperationException(token.Symbol);
}
return(double.NaN);
}
}
public static Func <double, double> CreateDelegate(TreeToken token, string variable, Parser parser, EvaluationOptions options)
{
var paramColl = new ParameterCollection <double>(variable);
var context = new EvaluationContext(options, paramColl);
var eval = new ExpressionTreeEvaluator(parser, context);
var expr = token.Evaluate(eval);
var parameters = paramColl.GetParameters();
return(Expression.Lambda <Func <double, double> >(expr, parameters).Compile());
}
public override Expression EvaluateVarFunction(VarFuncToken token)
{
Func <double, double> func;
switch (token.Symbol)
{
case ParserSymbols.Sum:
func = ExpressionTreeEvaluator.CreateDelegate(token.SubTokens[3],
token.VariableSymbol, parser, Context.Options);
return(iterateExpr(0, token.SubTokens[1], token.SubTokens[2], (v, i) => v + func(i)));
case ParserSymbols.Prod:
func = ExpressionTreeEvaluator.CreateDelegate(token.SubTokens[3],
token.VariableSymbol, parser, Context.Options);
return(iterateExpr(1, token.SubTokens[1], token.SubTokens[2], (v, i) => v * func(i)));
default:
if (Context.Options.StrictMode)
{
throw new UnsupportedOperationException(token.Symbol);
}
return(Expression.Constant(double.NaN));
}
}