使用 VBA 的离散函数

Question

我正在尝试使用 VBA 代码创建离散函数。
它有时会起作用，但我也收到了 "Subscript of range error" 消息。有谁能知道原因吗？

Function Discrete6()    
    Dim value As Variant, prob As Variant, i As Integer
    Dim uniform As Double, cumProb As Variant

    value = Array(5, 10, 12)
    prob = Array(0.2, 0.3, 0.5)
    uniform = Rnd
    cumProb = prob(1)

    i = 1
    Do Until cumProb > uniform
        i = i + 1
        cumProb = cumProb + prob(i)
    Loop

    Discrete6 = value(i)
End Function

Answer 1

以下修改有点脏，但它适用于您的特定情况（具有 3 个成员的数组）。

Function Discrete6()

Dim value As Variant, prob As Variant, i As Integer
Dim uniform As Double, cumProb As Variant

value = Array(5, 10, 12)
prob = Array(0.2, 0.5, 1)
uniform = Rnd

Select Case uniform
    Case Is <= prob(0)
        Discrete6 = value(0)
    Case Is > prob(1)
        Discrete6 = value(2)
    Case Else
        Discrete6 = value(1)
End Select

End Function