基于VBA的线性同余发生器
我试图在VBA中复制线性同余生成器,但我的过程返回错误“6”:溢出基于VBA的线性同余发生器,vba,excel,random,Vba,Excel,Random,我试图在VBA中复制线性同余生成器,但我的过程返回错误“6”:溢出 Sub test() Dim a As Long, c As Long, period As Long Dim seed As Long, sample As Long, max As Long Dim i As Long seed = 1234 sample = 2 max = 100 a = 48271 c = 0 period = 2 ^ 31
Sub test()
Dim a As Long, c As Long, period As Long
Dim seed As Long, sample As Long, max As Long
Dim i As Long
seed = 1234
sample = 2
max = 100
a = 48271
c = 0
period = 2 ^ 31 - 1
For i = 1 To sample
seed = (a * seed + c) Mod period
Next i
End Sub
我认为问题出在for循环的第一个表达式中
a*seed
在循环的第二步。
有没有不分裂地解决问题的建议
a*seed
在
您可以使用of variant并为小数编写自己的mod函数:
Function DecMod(a As Variant, n As Variant) As Variant
Dim q As Variant
q = Int(CDec(a) / CDec(n))
DecMod = a - n * q
End Function
Sub test()
Dim a As Variant, c As Variant, period As Variant
Dim seed As Variant, sample As Long, max As Long
Dim i As Long
seed = CDec(1234)
sample = 5
max = 100
a = CDec(48271)
c = 0
period = CDec(2 ^ 31 - 1)
For i = 1 To sample
Debug.Print seed
seed = DecMod(seed * a + c, period)
Next i
End Sub
输出:
1234
59566414
1997250508
148423250
533254358
@CallumDA我已经尝试将每个数字声明为一样长,但仍然会溢出调试函数说seed=(a*seed+c)Mod period我已经更新了你的问题,因此代码是最小的,并且可以立即重复——因为我已经更新了声明,问题仍然存在,所以我现在也删除了我的答案OK,非常感谢@马修金登,是的。我将
seed=
替换为Debug.Print
,效果很好-输出为59566414
。在Long
良好的解决方案(+1)的范围内。。。难道你不知道最初溢出的原因吗?我真的希望得到一个解释@在原始代码中(使用Long
),当VBA尝试将1234*59566414
作为Long求值时,溢出在循环的第二次传递中发生。如果其中一个操作数溢出,则即使生成的Mod
没有溢出,整个计算也会溢出。如果Mod
的实现更加健壮,那就太好了。
1234
59566414
1997250508
148423250
533254358