将 VBA 函数应用于矩阵/数据数组答案

【问题标题】：Applying VBA function to matrix/array of data将 VBA 函数应用于矩阵/数据数组
【发布时间】：2020-04-19 13:33:58
【问题描述】：

enter image description here我的乘法结果矩阵是 3x1。我想将我的 VBA 定义函数应用于结果矩阵 h，并创建一个新矩阵 h1。有什么建议可以改进此代码吗？在这种情况下，a for each 会更好吗？

感谢弗伦斯

Function sigmoid(X As Double) As Double
sigmoid = 1 / (1 + Exp(-X))
End Function

Sub arraymult()
    Dim i(0 To 2, 0 To 0) As Double
    Dim w(0 To 1, 0 To 2) As Double

i(0, 0) = 1
i(1, 0) = 2
i(2, 0) = 6

w(0, 0) = 2
w(0, 1) = 1
w(0, 2) = 1
w(1, 0) = 1
w(1, 1) = 1
w(1, 2) = 1

h = Application.WorksheetFunction.MMult(w, i)

        For j = 0 To 2
            h1(0, j) = sigmoid(h(0, j)) 'problem here
        Next j
End Sub

【问题讨论】：

"乘法的结果矩阵是 3x1。" - 真的吗？
i(3x1)* w(2x3)=h(3x1)
不应该是=h(3x3)吗？
2x1，我的错
将For j = 0 To 2改为For j = Lbound(h,1) to Ubound(h,1)和h1(0, j) = sigmoid(h(j, 1))你还需要声明h1:Dim h1() as variant和Redim h1(0 to 0, lbound(h,1) to Ubound(h ,1))`

标签： vba foreach matrix-multiplication

【解决方案1】：

您需要将数组声明为变体，然后在传递给函数时使用 Cdbl 使其成为双精度。

Function sigmoid(X As Double) As Double
    sigmoid = 1 / (1 + Exp(-X))
End Function

Sub arraymult()
    Dim i(0 To 2, 0 To 0) As Double
    Dim w(0 To 1, 0 To 2) As Double


    i(0, 0) = 1
    i(1, 0) = 2
    i(2, 0) = 6

    w(0, 0) = 2
    w(0, 1) = 1
    w(0, 2) = 1
    w(1, 0) = 1
    w(1, 1) = 1
    w(1, 2) = 1

    Dim h() As Variant
    h = Application.WorksheetFunction.MMult(w, i)

    Dim h1() As Variant
    ReDim h1(0 To 0, LBound(h, 1) To UBound(h, 1))

    For j = LBound(h, 1) To UBound(h, 1)
        h1(0, j) = sigmoid(CDbl(h(j, 1))) 'problem here
    Next j


End Sub

【讨论】：