我試圖實現使用Excel VB簡單的牛頓法迭代求解器(我從來沒有用過VB)循環離不開錯誤
我不斷收到錯誤loop without a Do
,我想不出什麼我」在這裏做錯了。
我試圖找到稱爲壓縮因子的函數z^3 - z^2 - (B^2 + B - A)z - A*B
的根源。
我的源MSN
Function zCalculation(ByVal temp As Double, ByVal press As Double) As Double
Dim tempCr As Double
Dim pressCr As Double
Dim A As Double
Dim B As Double
tempCr = temp/238.5
pressCr = press/547.424092
A = pressCr/tempCr
A = A/(9 * (2^(1/3) - 1))
B = pressCr/tempCr
B = B * (2^(1/3) - 1)/3
Dim zNot As Double
Dim counter As Integer
counter = 0
zNot = 1#
Do
counter = counter + 1
zNot = zNot - (zNot^3 - zNot^2 - (B^2 + B - A) * zNot - A * B)/(3 * zNot^2 - 2 * zNot - (B^2 + B - A))
If counter > 1000 Then
Exit Do
Loop Until eval(zNot, A, B) < 0.000001
zCalculation = zNot
End Function
休息
Function eval(ByVal z As Double, ByVal A As Double, ByVal B As Double) As Double
eval = z^3 - z^2 - (B^2 + B - A) * z - A * B
End Function
宕.....就是這樣。謝謝!不能相信我錯過了這一點。 –
不是你的錯............在這種情況下,Excel的錯誤信息是不正確的。 –
不能相信我確實在檢查這個之前在stackoverflow上搜索 – Tascalator