我可以设置功能吗？带有运行时变量的函数，以忽略在C＃中将它们作为参数传递吗？ [英] Can I set a Func<> function with runtime variables to omit passing them as parameters in C#?

问题描述

我有一个数值分析程序，为简单起见，它计算类似于以下算法：

I have a numerical analysis program which for simplicity calculates an algorithm similar to:

y = ax^3 + bx^2 + cx + d;

我在运行时计算a，b，c，d的值，并希望传递以下内容等价于 Func< double，double> 。

I calculate the values of a,b,c,d at runtime and would like to pass the following equivalent as a Func<double, double>. Where I can set a value for X, and get Y.

y = 12x^3 + 13x^2 + 14x + 15; 

其中12,13,14,15是运行时计算的数字。

Where 12,13,14,15 are the numbers calculated at runtime.

我意识到这可以通过传递双精度数组来完成，例如： Func< double []，double>
，但是我试图避免传递常量（可能很多）。

I realise this can be done by passing in a double array, like so: Func<double[], double> but I am trying to avoid passing around the constants (which can be many).

是否可以在运行时在func中设置这些数字？

（最好不对Func本身的a，b，c，d部分进行计算？对a，b，c， d是工作的80％）

(Preferably without making the calculation of a,b,c,d part of the Func<> itself? The calculation of a,b,c,d is 80% of the work)

例如：

a = ...

b = ...

c = ...

Func<x, double> {
     ((const)a) * x^3 +   ((const)b) * x^2 +   ((const)c) * x + 15;
}`

对于ABCD的每次评估-我都会评估10次。

For every evaluation of ABCD - I will evaluate 10 x's.

推荐答案

我不确定我是否完全理解您的要求，但是您可以尝试这样的方法吗？ / p>

I'm not sure if I understand quite what you are asking, but you could try something like this, perhaps?

Func<double, double> CreateCalculationFunc()
{
    double a = heavy calculation;
    double b = heavy calculation;
    double c = heavy calculation;
    double d = heavy calculation;

    Func<double, double> calculation = (x) =>
    {
        // You can use the constants in here without passing them as parameters
        return x * (a * b / c - d);
    };

    return calculation;
}

在这种情况下，您可以拨打 CreateCalculationFunc（），它将执行一次繁重的计算，并返回可重用的 Func< double，double> 进行变量计算。

In this case, you can just make a call to the CreateCalculationFunc(), which will do the heavy calculations once, and return a reusable Func<double,double> for doing your variable calculations.

当然，这可以扩展到任意数量的预先计算的常数和多个变量。

Of course, this is extensible to any amount of pre-calculated constants and more than one variable.

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