Excel transpose 2D array - Out of memory issue - arrays

Question

I have a VBA macro, where I want to write out an array to an Excel sheet.
I'm getting an "Out of memory" runtime error on some machines. I can run it easily on my development PC, but my client has issues with it.
Here I define my Values array:
Dim Values()
Dim idx As Long
idx = 0
Then I have a for cycle where I dynamically redim the array, and add my values to it:
for cycle...
ReDim Preserve Values(16, 0 To idx)
Values(0, idx) = "some text"
Values(1, idx) = "some other text"
....
Values(15, idx) = "last values for this row"
idx = idx + 1
next
Then here is where my code fails:
With ws
.Range(.Cells(1, 1), .Cells(1+ idx - 1, 16)).value = TransP(Values)
End With
Here's the TransP transposing function:
Public Function TransP(var As Variant) As Variant
Dim outP() As Variant, i As Long, j As Long
ReDim outP(LBound(var, 2) To UBound(var, 2), LBound(var, 1) To UBound(var, 1))
For i = LBound(outP) To UBound(outP)
For j = LBound(var) To UBound(var)
outP(i, j) = var(j, i)
Next
Next
TransP = outP
End Function
As I said, I can run the macro, and get something like 108770 rows. The same 108770 rows don't work on my clients PC.
I expect that the TransP function gives up on his PC, so should I split up the array into multiple smaller chunks, and write them 1 by 1?
Or my data model is not good?

Answer 1

You could also create a loop to write your output array row by row, it will take more time but you will most likely don't get out of memory error.
In the past when I've got out of memory issues with an arrays I just tried to perform actions using regular excel commands, in this case you could just copy range and than paste transposed values:
.PasteSpecial Paste:=xlPasteValues, Transpose:=True

Answer 2

Your method of appending elements to Values is inefficient because every time an element is added a new array is created and the values of the existing one copied to it. During this time twice the memory is in use, and if a large array is copied in this way multiple times in quick succession only heaven can know what demands are put on the RAM management.
The better way is to dimension the array larger than will be required (once), count the number of elements written to it and use Redim Preserve to reduce its size (once) when you are done.

Answer 3

I suspect this might be due to you not specifying the dimension in your TransP function. You are also defining your loops with both arrays. You've sized them identically (although with the dimensions switched) - Just use the same one to define your For loop
Public Function TransP(var As Variant) As Variant
Dim outP() As Variant, i As Long, j As Long
ReDim outP(LBound(var, 2) To UBound(var, 2), LBound(var, 1) To UBound(var, 1))
For i = LBound(outP, 1) To UBound(outP, 1)
For j = LBound(outP, 2) To UBound(outP, 2)
outP(i, j) = var(j, i)
Next
Next
TransP = outP
End Function

Answer 4

I don't think it's the TransP function, since that is already handling everything in a loop. I experienced the same sort of issue and there this error occured when I tried to transfer a large multidimensional array to a range.
My solution was to create a loop and do about a 1000 rows each time, but that depends on the clients pc I guess with how many rows you can do.
To take into account that var will not end on a certain step size, you could do a while loop:
i = 0
with ws
Do while i < Ubound(var)
max = application.worksheetfunction.max(1000,Ubound(var) - i) 'At some point, you could have less than 1000 left
.range(.cells(i+1,1), .cells(i+max)) = TransP(var,i,max)
i = i + 1000
Loop
In TransP you now use the lower- and upperbound of var, but if you add two variables from the loop, you can use them to only take a piece of the array.