/// <summary>
/// 转换成表达式字符串，自动判断是否加入括号
/// </summary>
/// <param name="v"></param>
/// <returns></returns>
public static string BlockToString(IExpr v)
{
if (v is ExprToken)
{
return(v.ToString());
}
else
{
return($"({v.ToString()})");
}
}
public static Func <double, double> Lambdify(IExpr expr, string variable)
{
//if (VariableCount(expr) != 1 || Variables(expr).Distinct().FirstOrDefault() != variable)
//{
// Console.WriteLine("Variable: " + variable);
// Console.WriteLine("Variable count: " + VariableCount(expr));
// Console.WriteLine("Variables: " + string.Join(", ", Variables(expr).Distinct().ToArray()));
// return null;
//}
return(x =>
{
var subtitution = Subtitute(expr, variable, new Constant(x));
var evaluation = Evaluate(subtitution);
if (evaluation is Constant)
{
return evaluation.ConstantValue();
}
else
{
Console.WriteLine("Lambdafication of the expr: " + expr.ToString() + " was not successful");
Console.WriteLine("After subtitution: " + subtitution.ToString());
Console.WriteLine("After eval: " + evaluation.ToString());
return double.NaN;
}
});
}
public bool Equals(IExpr other)
{
if (!(other is ExprValue))
{
return(false);
}
return(other.ToString() == this.ToString());
}
public static Func<double, double> Lambdify(IExpr expr, string variable)
{
//if (VariableCount(expr) != 1 || Variables(expr).Distinct().FirstOrDefault() != variable)
//{
// Console.WriteLine("Variable: " + variable);
// Console.WriteLine("Variable count: " + VariableCount(expr));
// Console.WriteLine("Variables: " + string.Join(", ", Variables(expr).Distinct().ToArray()));
// return null;
//}
return x =>
{
var subtitution = Subtitute(expr, variable, new Constant(x));
var evaluation = Evaluate(subtitution);
if (evaluation is Constant)
return evaluation.ConstantValue();
else
{
Console.WriteLine("Lambdafication of the expr: " + expr.ToString() + " was not successful");
Console.WriteLine("After subtitution: " + subtitution.ToString());
Console.WriteLine("After eval: " + evaluation.ToString());
return double.NaN;
}
};
}