Semantic Kernel开发实践：Planner 规划器

前言

Semantic Kernel Planner 是一款动态工具，可以将用户的请求转换为可执行的计划。换句话说，当它接收到用户请求（目标）后，根据Kernel对象具有的能力（提供的Plugin和Function），自动组合。

由于Planner的自动规划，很可能产生不可预期的执行顺序、不适合的Function的调用，因此这很大的决定因素是编写的Prompt和Function上定义的描述是否准备合理。

准备Plugin

对于Native Function，需要使用特性进行声明，KernelFunction表名可以被Semantic Kernel调用的Function，Descrption用来描述Function和参数的语义含义。

public sealed class MathPlugin
{
    [KernelFunction, Description("Take the square root of a number")]
    public static double Sqrt(
        [Description("The number to take a square root of")]
        double number1
    )
    {
        return Math.Sqrt(number1);
    }

    [KernelFunction, Description("Add two numbers")]
    public static double Add(
        [Description("The first number to add")]
        double number1,
        [Description("The second number to add")]
        double number2
    )
    {
        return number1 + number2;
    }

    [KernelFunction, Description("Subtract two numbers")]
    public static double Subtract(
        [Description("The first number to subtract from")]
        double number1,
        [Description("The second number to subtract away")]
        double number2
    )
    {
        return number1 - number2;
    }

    [KernelFunction, Description("Multiply two numbers. When increasing by a percentage, don't forget to add 1 to the percentage.")]
    public static double Multiply(
        [Description("The first number to multiply")]
        double number1,
        [Description("The second number to multiply")]
        double number2
    )
    {
        return number1 * number2;
    }

    [KernelFunction, Description("Divide two numbers")]
    public static double Divide(
        [Description("The first number to divide from")]
        double number1,
        [Description("The second number to divide by")]
        double number2
    )
    {
        return number1 / number2;
    }

    [KernelFunction, Description("Raise a number to a power")]
    public static double Power(
        [Description("The number to raise")] double number1,
        [Description("The power to raise the number to")]
        double number2
    )
    {
        return Math.Pow(number1, number2);
    }

    [KernelFunction, Description("Take the log of a number")]
    public static double Log(
        [Description("The number to take the log of")]
        double number1,
        [Description("The base of the log")] double number2
    )
    {
        return Math.Log(number1, number2);
    }

    [KernelFunction, Description("Round a number to the target number of decimal places")]
    public static double Round(
        [Description("The number to round")] double number1,
        [Description("The number of decimal places to round to")]
        double number2
    )
    {
        return Math.Round(number1, (int)number2);
    }

    [KernelFunction, Description("Take the absolute value of a number")]
    public static double Abs(
        [Description("The number to take the absolute value of")]
        double number1
    )
    {
        return Math.Abs(number1);
    }

    [KernelFunction, Description("Take the floor of a number")]
    public static double Floor(
        [Description("The number to take the floor of")]
        double number1
    )
    {
        return Math.Floor(number1);
    }

    [KernelFunction, Description("Take the ceiling of a number")]
    public static double Ceiling(
        [Description("The number to take the ceiling of")]
        double number1
    )
    {
        return Math.Ceiling(number1);
    }

    [KernelFunction, Description("Take the sine of a number")]
    public static double Sin(
        [Description("The number to take the sine of")]
        double number1
    )
    {
        return Math.Sin(number1);
    }

    [KernelFunction, Description("Take the cosine of a number")]
    public static double Cos(
        [Description("The number to take the cosine of")]
        double number1
    )
    {
        return Math.Cos(number1);
    }

    [KernelFunction, Description("Take the tangent of a number")]
    public static double Tan(
        [Description("The number to take the tangent of")]
        double number1
    )
    {
        return Math.Tan(number1);
    }

    [KernelFunction, Description("Take the arcsine of a number")]
    public static double Asin(
        [Description("The number to take the arcsine of")]
        double number1
    )
    {
        return Math.Asin(number1);
    }

    [KernelFunction, Description("Take the arccosine of a number")]
    public static double Acos(
        [Description("The number to take the arccosine of")]
        double number1
    )
    {
        return Math.Acos(number1);
    }

    [KernelFunction, Description("Take the arctangent of a number")]
    public static double Atan(
        [Description("The number to take the arctangent of")]
        double number1
    )
    {
        return Math.Atan(number1);
    }
}

使用Planner

1、使用Planner需要引入依赖包Microsoft.SemanticKernel.Planners.Handlebars，创建Planner对象

var planner = new HandlebarsPlanner(new HandlebarsPlannerOptions { AllowLoops = true });

2、定义用户请求目标，在根据目标创建执行。

var goal = "算一下我有多少钱。如果首先我的投资 2130.23 元增加了 23%，然后我花 25 元买了一杯咖啡";
var plan = await planner.CreatePlanAsync(kernel, goal);

3、调用计划，获得结果。

这里调用的计划不稳定，最好要放到try-catch块中进行异常捕获

如果想查看计划内容，可以使用plan.ToString()查看

var result = await plan.InvokeAsync(kernel);
Console.WriteLine("Result: " + result);

执行结果截图

总结

本篇文章中，我主要讲解并演示了Planner，在运行时会发现计划并不是总能执行成功，主要原因还是因为Planner的规划非常依赖用户的Prompt和Plugin的语义化描述。

感谢你的阅读，祝您编码愉快！