Hello. I can't tell if you are trying to do Convolution, or Correlation. I
can't tell how far you are trying to pass the Filter (based on the op.) If
you are doing Convolution with 100's (or up to 2048 data points per array),
you may want to consider Excel's FFT. It is under <Tools> <Data Analysis>.
(Convolution of two equal size arrays...Convolution of n+m-1 must be <= 4096
in Excel) I find it easier to keep the least significant bits at the top of
the array for fft.
If not, perhaps another option for your function...
Function Convoloution(Array1 As Range, Array2 As Range)
'// Full overlap only!
Dim N As Long
Dim j As Long
Dim Final As Variant
Final = 0
N = Array1.Cells.Count + 1
For j = 1 To N - 1
Final = Final + (Array1(j) * Array2(N - j))
Next
Convoloution= Final
End Function
1 0 0 a 1*a
1 2 0 * b = 1*b+2*a
1 2 3 c 1*c+2*b+3*a
Using another program to check, here is a shortcut for Convolution using
Fourier Analysis. Here, it is stopped at full overlap.
ListConvolve[{1, 2, 3}, {a, b, c}, {1, 1}, 0]
a, 2*a + b, 3*a + 2*b + c
--
Dana DeLouis
Using Windows XP & Office XP
= = = = = = = = = = = = = = = = =
The pourpose of this is Hydrology (deconvoloution is a
hydrology term).
We have a column in Excel, for example [[1] [2] [3]]
and are muliplying it by a column [[a]
[c]]
but we really want the matricies multiplied like:
1 0 0 a 1*a
1 2 0 * b = 1*b+2*a
1 2 3 c 1*c+2*b+3*a
of course our colums include 100's of values
Thank you for your help.
-----Original Message-----
Josh,
Like Jim said, use the Range object's row counting capability, and then you
can ditch the Array3 variable.
Function Deconvoloution(Array1 As Range, Array2 As Range)
Dim x As Integer
Dim y As Integer
Dim Final
If Array1.Rows.Count <> Array2.Rows.Count Then
Msgbox "Mismatched number of rows in passed Ranges.", vbCritical,
"Parameter Error"
Exit Function
Else
x = Array1.Rows.Count
End If
Final = 0
y = 1
Do Until x = 0
Final = Final + (Array1(y) * Array2(x))
x = x - 1
y = y + 1
Loop
Deconvoloution = Final
End Function
Just out of curiousity; what is the purpose of this kind of inverted
SumProduct that you're doing?
Thanks,
Mark
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