VBA寻根槽对分法

当我知道函数的根不是0时，我的vba代码会不断返回值0

这是非常简单的代码，但我似乎无法调试它。知道这个错误可能来自哪里吗

Option Explicit

Public Function Bisect(ByVal xlow As Double, ByVal xhigh As Double) As Double

Dim i As Integer
Dim xmid As Double

xmid = (xlow + xhigh) / 2

For i = 1 To 100

If f(xlow) * f(xmid) < 0 Then
    xhigh = xmid
    xmid = (xlow + xhigh) / 2
Else
    xlow = xmid
    xmid = (xlow + xhigh) / 2
End If

Next i

Bisect = xmid

End Function

Function f(ByVal x As Double, Optional ByRef inputArray As Range) As Variant

Dim ca0 As Double
Dim v0 As Double
Dim k As Double
Dim e As Double
Dim ac As Double
Dim L As Double

inputArray(2, 2) = ca0
inputArray(3, 2) = v0
inputArray(4, 2) = k
inputArray(5, 2) = e
inputArray(6, 2) = ac
inputArray(7, 2) = L

f(x) = (v0 / (k * ca0 * ac)) * ((2 * e * (1 + e) * Log(1 - x)) + (e ^ 2 * x) + (((1 + e) ^ 2 * x) / (1 - x))) - L

End Function

选项显式
公共函数对分（ByVal xlow为双精度，ByVal xhigh为双精度）为双精度
作为整数的Dim i
Dim xmid为双精度
xmid=（xlow+xhigh）/2
对于i=1到100
如果f（xlow）*f（xmid）<0，则
xhigh=xmid
xmid=（xlow+xhigh）/2
其他的
xlow=xmid
xmid=（xlow+xhigh）/2
如果结束
接下来我
对分=xmid
端函数
函数f（ByVal x作为双精度函数，可选ByRef inputArray作为范围）作为变量
暗淡的ca0为双色
尺寸v0为双精度
把k调成双色
把e调成双色
将交流调暗为双
我是双人的
输入阵列（2，2）=ca0
输入阵列（3，2）=v0
输入阵列（4，2）=k
输入阵列（5，2）=e
输入阵列（6，2）=交流
输入阵列（7，2）=L
f（x）=（v0/（k*ca0*ac））*（（2*e*（1+e）*对数（1-x））+（e^2*x）+（（1+e^2*x）/（1-x））-L
端函数

是否可能是您试图用空变量分配inputarray

我认为应该是：

ca0 = inputArray(2, 2)
v0 = inputArray(3, 2) 

等等

我猜

f(x) = (v0 / (k * ca0 * ac)) * ((2 * e * (1 + e) * Log(1 - x)) + (e ^ 2 * x) + (((1 + e) ^ 2 * x) / (1 - x))) - L

应该是

f = (v0 / (k * ca0 * ac)) * ((2 * e * (1 + e) * Log(1 - x)) + (e ^ 2 * x) + (((1 + e) ^ 2 * x) / (1 - x))) - L

' i Think you want to take those constant values from cells presentin the sheet

Function f(ByVal x As Double) As Variant


Dim inputArray As Range

Dim ca0 As Double
Dim v0 As Double
Dim k As Double
Dim e As Double
Dim ac As Double
Dim L As Double

' i Think you want to take values from cells in the sheet

ca0 = ActiveSheet.Cells(2, 2).Value
v0 = ActiveSheet.Cells(3, 2).Value
k = ActiveSheet.Cells(4, 2).Value
e = ActiveSheet.Cells(5, 2).Value
ac = ActiveSheet.Cells(6, 2).Value
L = ActiveSheet.Cells(7, 2).Value