Return array in Spreadsheet Function - arrays

Question

The code below returns an array. I would like to use it in a spread sheet as an excel formula to return the array. However, when I do, it only returns the first value to the cell. Is there anyway to return the array in a range of equal size as the array?
Function LoadNumbers(Low As Long, High As Long) As Long()
'''''''''''''''''''''''''''''''''''''''
' Returns an array of Longs, containing
' the numbers from Low to High. The
' number of elements in the returned
' array will vary depending on the
' values of Low and High.
''''''''''''''''''''''''''''''''''''''''
'''''''''''''''''''''''''''''''''''''''''
' Declare ResultArray as a dynamic array
' to be resized based on the values of
' Low and High.
'''''''''''''''''''''''''''''''''''''''''
Dim ResultArray() As Long
Dim Ndx As Long
Dim Val As Long
'''''''''''''''''''''''''''''''''''''''''
' Ensure Low <= High
'''''''''''''''''''''''''''''''''''''''''
If Low > High Then
Exit Function
End If
'''''''''''''''''''''''''''''''''''''''''
' Resize the array
'''''''''''''''''''''''''''''''''''''''''
ReDim ResultArray(1 To (High - Low + 1))
''''''''''''''''''''''''''''''''''''''''
' Fill the array with values.
''''''''''''''''''''''''''''''''''''''''
Val = Low
For Ndx = LBound(ResultArray) To UBound(ResultArray)
ResultArray(Ndx) = Val
Val = Val + 1
Next Ndx
''''''''''''''''''''''''''''''''''''''''
' Return the array.
''''''''''''''''''''''''''''''''''''''''
LoadNumbers = ResultArray()
End Function

Answer 1

A UDF can certainly return an array, and your function works fine. Just select, e.g., range B2:D2, put =LoadNumbers(1, 3) into the formula bar, and hit Ctrl+Shift+Enter to tell Excel it's an array function.
Now, you can't have the UDF auto-resize the range it was called from according to its inputs (at least not without some ugly Application.OnTime hack), but you don't need to do that anyways. Just put the function in a 1000-cell-wide range to begin with, and have the UDF fill in the unused space with blank cells, like this:
Function LoadNumbers(ByVal Low As Long, ByVal High As Long) As Variant()
Dim ResultArray() As Variant
Dim Ndx As Long
Dim Val As Long
Dim SourceCols As Long
SourceCols = Application.Caller.Columns.Count
If Low > High Then
Exit Function
End If
If High - Low + 1 > SourceCols Then High = Low + SourceCols - 1
ReDim ResultArray(1 To SourceCols)
Val = Low
For Ndx = LBound(ResultArray) To (High - Low + 1)
ResultArray(Ndx) = Val
Val = Val + 1
Next Ndx
For Ndx = (High - Low + 2) To UBound(ResultArray)
ResultArray(Ndx) = vbNullString
Next Ndx
LoadNumbers = ResultArray()
End Function

Answer 2

A worksheet formula can only output a value to the same cell the formula was written in. As it stands, the code already produces an array. If you want the values to be shown as you copy the formula down, use a formula like this (in any cell you want) and then copy down:
=INDEX(LoadNumbers(1,10),ROWS($A$1:$A1))
If you copy down too far, you'll get a #REF! error because the LoadNumbers ran out of numbers.

Answer 3

I was looking for something similar (create a function in a macro, take inputs from a sheet, output an multi-dim array), and I hope my use-case below helps to answer. If not, my apologies:
Use-case:
Create and apply well-known numerical option valuation function, and output the stock price, valuation, and payoff as a 3-D array (3 columns) of #rows as specified in the function (20 in this case, as NAS variable). The code is copied - but the idea is to get the output into the sheet....
a) These inputs are static in the sheet.
b) I called the macro formula 'optval' via the 'fx' function list from an output cell I wanted to start in, and put the starting inputs into the formula.
b) The output will propagate to the cells as per the code using the NAS bound of 20 rows. Trivial, but it works.
c) you can automate the execution of this and output to the sheet - but anyhow, I hope this way helps anyway.
The module function is below (copied!) - but just put the starter inputs in i.e.
Vol=.2, Int rate = 0.05, Strike=120, Exp = 1, P type = C (or P), US?= N, i.e. european, , NAS=20 (or however many rows you want to see, and it affects the granularity of the numerical method)
Function optval(Vol, Intrate, Strike, Expn, Ptype, Etype, NAS)
ReDim S(0 To NAS) As Double
ReDim VOld(0 To NAS) As Double
ReDim VNew(0 To NAS) As Double
ReDim dummy(0 To NAS, 1 To 3)
dS = 2 * Strike / NAS
dt = 0.9 / NAS / NAS / Vol / Vol
NTS = Int(Expn / dt) + 1
dt = Expn / NTS
q = 1
If Ptype = "P" Then q = -1
For i = 0 To NAS
S(i) = i * dS
VOld(i) = Application.Max(q * (S(i) - Strike), 0)
dummy(i, 1) = S(i)
dummy(i, 2) = VOld(i) 'Payoff
Next i
For k = 1 To NTS
For i = 1 To NAS - 1
Delta = (VOld(i + 1) - VOld(i - 1)) / 2 / dS
Gamma = (VOld(i + 1) - 2 * VOld(i) + VOld(i - 1)) / dS / dS
Theta = -0.5 * Vol * Vol * S(i) * S(i) * Gamma - _
Intrate * S(i) * Delta + Intrate * VOld(i)
VNew(i) = VOld(i) - Theta * dt 'BSE
Next i
VNew(0) = VOld(0) * (1 - Intrate * dt) 'S=0
VNew(NAS) = 2 * VNew(NAS - 1) - VNew(NAS - 2) 'Infty
For i = 0 To NAS
VOld(i) = VNew(i)
Next i
If Etype = "Y" Then
For i = 0 To NAS
VOld(i) = Application.Max(VOld(i), dummy(i, 2))
Next i
End If
Next k
For i = 0 To NAS
dummy(i, 3) = VOld(i)
Next i
optval = dummy
End Function

Answer 4

=INDEX(LoadNumbers(1,10),ROWS($A$1:$A1),COLUMNS($B$1,B$1))