Matlab 如何正确计算两个向量中的匹配对数 请让我们考虑这个代码 function averageentropy=calculate(f,y) count1=0; count0=0; n=length(f); n1=0; n0=0; entrop1=0; entrop2=0; bigp=sum(f)/n; indf1 = f == 1; indf0 = ~indf1 ; indy1 = y == 1; indy0 = ~indy1 ; count1 = sum(indf1 & indy1) ; count0 = sum(indf0 & indy0) ; n1 = sum(indf1); n0 = sum(indf0); smallpplus=count1/n1; smallpminus=count0/n0; if smallpplus==0 || (1-smallpplus==0) entrop1=0; else entrop1=-smallpplus*log2(smallpplus)-(1- smallpplus)*log2(1- smallpplus); end if smallpminus==0 || (1-smallpminus==0) entrop2=0; else entrop2=-smallpminus*log2(smallpminus)-(1- smallpminus)*log2(1- smallpminus); end averageentropy=bigp*entrop1+(1-bigp)*entrop2; end 我要下面的事情，首先考虑F2和Y的数据。 f2 0 0 0 1 1 1 0 1

及

我想计算以下步骤

1.计算bigp，它等于f2中1的数量除以f2的长度，这个代码在这部分做得很好

我想计算y中1的个数，其中f2=1

2.1我将小p+定义为该数字除以f2中的数字1

3.我想计算y中1的个数，其中f2=0

3.1我将小p减定义为该数字除以f2的总数=0

最后我想计算平均熵，公式在代码中给出

应该得到的是0.47，但我得到的是0.4，pl；请帮我修一下

更新 我认为这一行应该是错误的

count1 = sum(indf1 & indy1) ;
count0 = sum(indf0 & indy1) ;

更准确地说

count0 = sum(indf0 & indy1) 

count0 =

     3

有错误，必须有3/8=0.375

因为你说“我用Excel做了这个计算，我知道正确的答案是什么”，我决定将你上面的代码“转换回Excel”（准确地说是VBA）。当我对给定的两个向量进行计算时，得到的熵大约是0.4（即0.3936）——而不是你声称应该得到的0.47

那么，“正确”的答案是什么？你是如何知道的

我问这个问题的原因是：一旦我们有了任何语言的“工作代码”，如果你在翻译方面遇到困难，我们可以帮助你。但是当我们不知道你想做什么时（这可能只是语言障碍），我们帮不了你

作为参考，以下是您在VBA中的上述代码：让我们按照您的意图来做，然后我们将进行翻译。好吗

Option Explicit

Function calculateEntropy(f, y)
Dim indf1(), indf0(), indy1(), indy0()
Dim count0, count1
Dim n, n0, n1, ii
Dim entrop1, entrop2
Dim bigp, littlep, smallPplus, smallPminus

count1 = 0
count0 = 0
n = UBound(f)
ReDim indf1(1 To n)
ReDim indf0(1 To n)
ReDim indy1(1 To n)
ReDim indy0(1 To n)

n1 = 0
n0 = 0
entrop1 = 0
entrop2 = 0
count1 = 0
count0 = 0

bigp = WorksheetFunction.Sum(f) / n

For ii = 1 To n
  If (f(ii) = 1) Then
    indf1(ii) = 1
    indf0(ii) = 0
  Else
    indf1(ii) = 0
    indf0(ii) = 1
  End If

  If (y(ii) = 1) Then
    indy1(ii) = 1
    indy0(ii) = 0
  Else
    indy1(ii) = 0
    indy0(ii) = 1
  End If

Next ii

For ii = 1 To n
  n1 = n1 + indf1(ii)
  n0 = n0 + indf0(ii)
  If (indf1(ii) = 1 And indy1(ii) = 1) Then count1 = count1 + 1
  If (indf1(ii) = 0 And indy0(ii) = 0) Then count0 = count0 + 1
Next ii

smallPplus = count1 / n1
smallPminus = count0 / n0
If smallPplus = 0 Or (1 - smallPplus) = 0 Then
  entrop1 = 0
Else
  entrop1 = -smallPplus * Log(smallPplus) - (1 - smallPplus) * Log(1 - smallPplus)
End If

If smallPminus = 0 Or (1 - smallPminus) = 0 Then
  entrop2 = 0
Else
  entrop2 = -smallPminus * Log(smallPminus) - (1 - smallPminus) * Log(1 - smallPminus)
End If

' note - have to divide whole thing by Log(2) since VBA does not have LOG2() function built in)
calculateEntropy = (bigp * entrop1 + (1 - bigp) * entrop2) / Log(2)

End Function

Sub test()
Dim f()
Dim y()
f = Array(0, 0, 0, 1, 1, 1, 0, 1)
y = Array(1, 1, 1, 0, 0, 0, 0, 0)

MsgBox "entropy is " & calculateEntropy(f, y)

End Sub

---

打印中间结果以查找不符合您期望的结果。你的问题应该只是一行。不要让我们在大海捞针——这是你的任务。我已经更新了我的想法是否应该有错误——只需给出一个输入和输出数据的样本。您的代码显示了您的尝试，但它并没有让我们理解问题如下，对于输入两个向量f2和y，我们希望在f2=1的位置计算y中的1个数，当f2=0DAT时，计算y=1的数。您已经在这里激活了此问题：

Option Explicit

Function calculateEntropy(f, y)
Dim indf1(), indf0(), indy1(), indy0()
Dim count0, count1
Dim n, n0, n1, ii
Dim entrop1, entrop2
Dim bigp, littlep, smallPplus, smallPminus

count1 = 0
count0 = 0
n = UBound(f)
ReDim indf1(1 To n)
ReDim indf0(1 To n)
ReDim indy1(1 To n)
ReDim indy0(1 To n)

n1 = 0
n0 = 0
entrop1 = 0
entrop2 = 0
count1 = 0
count0 = 0

bigp = WorksheetFunction.Sum(f) / n

For ii = 1 To n
  If (f(ii) = 1) Then
    indf1(ii) = 1
    indf0(ii) = 0
  Else
    indf1(ii) = 0
    indf0(ii) = 1
  End If

  If (y(ii) = 1) Then
    indy1(ii) = 1
    indy0(ii) = 0
  Else
    indy1(ii) = 0
    indy0(ii) = 1
  End If

Next ii

For ii = 1 To n
  n1 = n1 + indf1(ii)
  n0 = n0 + indf0(ii)
  If (indf1(ii) = 1 And indy1(ii) = 1) Then count1 = count1 + 1
  If (indf1(ii) = 0 And indy0(ii) = 0) Then count0 = count0 + 1
Next ii

smallPplus = count1 / n1
smallPminus = count0 / n0
If smallPplus = 0 Or (1 - smallPplus) = 0 Then
  entrop1 = 0
Else
  entrop1 = -smallPplus * Log(smallPplus) - (1 - smallPplus) * Log(1 - smallPplus)
End If

If smallPminus = 0 Or (1 - smallPminus) = 0 Then
  entrop2 = 0
Else
  entrop2 = -smallPminus * Log(smallPminus) - (1 - smallPminus) * Log(1 - smallPminus)
End If

' note - have to divide whole thing by Log(2) since VBA does not have LOG2() function built in)
calculateEntropy = (bigp * entrop1 + (1 - bigp) * entrop2) / Log(2)

End Function

Sub test()
Dim f()
Dim y()
f = Array(0, 0, 0, 1, 1, 1, 0, 1)
y = Array(1, 1, 1, 0, 0, 0, 0, 0)

MsgBox "entropy is " & calculateEntropy(f, y)

End Sub