Calculating a Sum - vba

Question

What I am trying to do is develop a model that takes a cell that is greater than 1 then to take the sum of the area to the first row using a cone shape, so for example cell D4, sum the area C3:C5 + B2:B6 + A1:A7.
At the moment I have this but it obviously is not working.
Dim I As Double
Dim J As Double
Dim Size As Integer
Dim x As Integer
Dim y As Integer
Dim z As Integer
'Dim Range As Integer
Dim PV1 As Integer
'MCArray = Worksheets("Data")
I = WorksheetFunction.CountA(Worksheets("Data").Rows(1))
J = WorksheetFunction.CountA(Worksheets("Data").Columns(1))
'Loop to Move down the rows
For x = 1 To J
'Loop to move acoss the columns
For y = 1 To I
'IfElse to determine if cell value is greater or equal to zero
If Cells(J, I).Value >= 0 Then
'Loop to sum the cells above
For z = 1 To J
PV1 = (ActiveCell.Value) + Worksheet.Sum(Range([J - z], [I-z:I+z]))
'IfElse to determine if final sum is greater than zero
If PV1 > 0 Then
Worksheets("MC").Range("B4").Value = PV1
Range([J - z], [I-z:I+z]).Interior.ColourIndex = 1
End If
Next z
End If
Next y
Next x

Answer 1

Here is a function you can use either as a UDF or from another routine. Just pass it the single cell you want to start from (D4 in your example) and this function will calculate the sum of the cone as you described.
Public Function SUMCONE(r As Range) As Double
Application.Volatile
SUMCONE = Application.Sum(r, r(-0, -0).Resize(, 3), r(-1, -1).Resize(, 5), r(-2, -2).Resize(, 7))
End Function
Here is an example of how to use the above function from your VBA routine:
Public Sub Demo()
Dim j&
For j = 5 To 10
If Cells(5, j) > 0 Then
Debug.Print SUMCONE(Cells(5, j))
End If
Next
End Sub
UPDATE
Based on your feedback I have updated the function and the demo routine to form an upward cone summation from the initial cell.
UPDATE #2
The above is for a fixed-size cone, extending upwards, that can be initiated from any cell in the worksheet.
But if you would prefer for the cone to always extend all the way up to row 1 regardless of which cell it originates in, then the following is what you are after:
Public Sub Demo()
Dim i&, j&
For j = 1 To Application.CountA(Worksheets("Data").Rows(1))
For i = 1 To Application.CountA(Worksheets("Data").Columns(1))
If Cells(i, j) > 0 Then
Debug.Print Cells(i, j).Address, SumAndColorCone(Cells(i, j))
End If
Next
Next
End Sub
Public Function SumAndColorCone(r As Range) As Double
Dim i&, k&, c As Range
Set c = r
For i = r.Row - 1 To 1 Step -1
Set c = Union(c, r(-k, -k).Resize(, (k + 1) * 2 + 1))
k = k + 1
Next
c.Interior.Color = vbRed
SumAndColorCone = Application.Sum(c)
End Function
UPDATE #3
As I suspected there was a problem if the cone was initiated too close to the left edge of the worksheet. I've added code to handle that now. Also your method for accessing the large matrix (which I had used in the Demo routine) did not work properly. I fixed that as well:
Public Sub Demo()
Dim i&, j&
For j = 1 To Cells(1, Columns.Count).End(xlToLeft).Column
For i = 1 To Cells(Rows.Count, "A").End(xlUp).Row
If Val(Cells(i, j)) > 0 Then
Debug.Print Cells(i, j).Address, SumAndColorCone(Cells(i, j))
End If
Next
Next
End Sub
Public Function SumAndColorCone(r As Range) As Double
Dim i&, k&, c As Range
Set c = r
For i = r.Row - 1 To 1 Step -1
If r.Column - k < 2 Then Exit For
Set c = Union(c, r(-k, -k).Resize(, (k + 1) * 2 + 1))
k = k + 1
Next
c.Interior.Color = vbRed
SumAndColorCone = Application.Sum(c)
End Function