Question

我试图创建一个棒球赛季模拟器，看看一个糟糕的投手会对球队的总冠军赔率造成多大影响。所以我基本上为季后赛创造了一个模拟器（3轮，第一轮最好是5轮，接下来的两轮最好是7轮）。我可以看到，如果他每三场比赛投球一次，SP会对球队造成多大伤害，并且他的获胜几率降低10％。

为了确保我写这个，我首先运行我的模拟没有任何调整，所以每个游戏两个团队都有50％的机会赢得...（因此一个团队有12.5％的机会赢得世界系列赛然而，在3轮季后赛中，我的得分始终高于12.5。

我感觉问题出在Rnd功能上，所以我玩了一下（添加了一个功能，试图改变时间等），现在我的模拟结果是<12.5％。然后我试图麻烦拍摄并注意到在每一轮都没有赢得50％的时间......每次我重新运行模拟就是这种情况（就像第一轮将获得47％的成功然后第二轮51 ％然后第三轮58％...然后下一轮将回归46％，52％，59％。

我做错了什么，或者这只是rnd函数处理不好的东西？

Public Function wRandomNumber(lowerbound, upperbound, Optional rndType = 1) As Double
Dim rndVariable As Double
'Const ms As Double = 0.000000011574

Randomize Timer
'Application.Wait Now + ms * 1
rndVariable = Rnd
If rndType = 1 Then
    wRandomNumber = Int((upperbound - lowerbound + 1) * rndVariable + lowerbound)
ElseIf rndType = 2 Then
    If (upperbound - lowerbound + 1) * rndVariable + lowerbound <= upperbound Then
        wRandomNumber = (upperbound - lowerbound + 1) * rndVariable + lowerbound
    Else
        Do While (upperbound - lowerbound + 1) * rndVariable + lowerbound > upperbound
            rndVariable = Rnd
            If (upperbound - lowerbound + 1) * rndVariable + lowerbound <= upperbound Then
                wRandomNumber = (upperbound - lowerbound + 1) * rndVariable + lowerbound
            End If
        Loop
    End If
End If
End Function

Public Sub Playoff_sim()

Dim game_num As Integer
Dim lds_wins_stros As Integer
Dim lds_loss_stros As Integer
Dim lcs_wins_stros As Integer
Dim lcs_loss_stros As Integer
Dim ws_wins_stros As Integer
Dim ws_loss_stros As Integer
Dim p As Double
Dim outcome1 As Single
Dim outcome2 As Single
Dim outcome3 As Single
Dim i As Double
Dim iter As Double
Dim CHAMPS As Double
Dim Loser As Double
Dim p_bad As Double
Dim p_norm As Double
Dim lds_champs As Double
Dim lcs_champs As Double
Dim r As Double
Const ms As Double = 0.000000011574

iter = 100000
CHAMPS = 0
Loser = 0
lds_champs = 0
lcs_champs = 0
p_bad = 0.5
p_norm = 0.5
r = 0
For i = 1 To iter

game_num = 1
lds_wins_stros = 0
lds_loss_stros = 0
lcs_wins_stros = 0
lcs_loss_stros = 0
ws_loss_stros = 0
ws_wins_stros = 0

Do Until lds_wins_stros = 3 Or lds_loss_stros = 3

outcome1 = wRandomNumber(0, 1, 2)
    If game_num = 3 Then
        p = p_bad
    Else
        p = p_norm
    End If

    If p > outcome1 Then
        lds_wins_stros = lds_wins_stros + 1
    Else
        lds_loss_stros = lds_loss_stros + 1
    End If
    r = r + 1
    'Worksheets("Playoff_Sim").Cells(r, 15).Value = outcome1

game_num = game_num + 1
Loop

If lds_wins_stros = 3 Then

    outcome2 = wRandomNumber(0, 1, 2)
    lds_champs = 1 + lds_champs
    Do Until lcs_wins_stros = 4 Or lcs_loss_stros = 4

    If game_num = 3 Or 6 Or 9 Or 12 Or 15 Or 18 Or 21 Then
        p = p_bad
    Else
        p = p_norm
    End If

    If p > outcome2 Then
        lcs_wins_stros = lcs_wins_stros + 1
    Else
        lcs_loss_stros = lcs_loss_stros + 1
    End If

    game_num = game_num + 1

    Loop

    If lcs_wins_stros = 4 Then
        lcs_champs = lcs_champs + 1

        outcome3 = wRandomNumber(0, 1, 2)
        Do Until ws_wins_stros = 4 Or ws_loss_stros = 4

            If game_num = 3 Or 6 Or 9 Or 12 Or 15 Or 18 Or 21 Then
                p = p_bad
            Else
                p = p_norm
            End If

            If p > outcome3 Then
                ws_wins_stros = ws_wins_stros + 1
            Else
                ws_loss_stros = ws_loss_stros + 1
            End If
        'r = r + 1
        game_num = game_num + 1
        'Worksheets("Playoff_Sim").Cells(r, 15).Value = outcome3
        Loop

        If ws_wins_stros = 4 Then
            CHAMPS = CHAMPS + 1
        Else
            Loser = Loser + 1
        End If

    Else
        Loser = Loser + 1
    End If

Else
    Loser = Loser + 1
End If

Next i

Worksheets("Playoff_Sim").Cells(2, 1).Value = CHAMPS
Worksheets("Playoff_Sim").Cells(2, 2).Value = Loser
Worksheets("Playoff_Sim").Cells(2, 3).Value = lds_champs
Worksheets("Playoff_Sim").Cells(2, 4).Value = lcs_champs

End Sub

Answer 1

问题不仅仅是随机数（可以通过@ A.S.H建议使用Application.RandBetween解决），但也是模拟的逻辑。两次重复的代码片段

If game_num = 3 Or 6 Or 9 Or 12 Or 15 Or 18 Or 21 Then
    p = p_bad
Else
    p = p_norm
End If

相当于单行p = p_bad。这是因为条件game_num = 3 Or 6 Or 9 Or 12 Or 15 Or 18 Or 21始终评估为True，因为您只是将game_num与3进行比较，然后强制VBA解释其余数字（6,9,15， 18,21）使用True运算符作为Or。相反，只需：

If game_num Mod 3 = 0 Then
    p = p_bad
Else
    p = p_norm
End If

也可能存在其他问题，但这应该足以让你开始。

模拟中的VBA随机数

1 个答案: