Question

I have a 10 period cost curve table below. How do I programmatically collapse/condense/shrink this to 4 periods. I’m using VBA but I should be able to follow other languages. The routine should work for whatever period you pass to it. For example, if I pass it a 7 it should condense the percentages to 7 periods. If I pass it 24 then expand the percentages to 24 periods, spreading the percentages based on the original curve. Any help or example will be appreciated. Thanks…

ORIGINAL
Period  Pct
1       10.60%
2       19.00%
3       18.30%
4       14.50%
5       10.70%
6        8.90%
7        6.50%
8        3.10%
9        3.00%
10       5.40%

COLLAPSED
Period  Pct
1       38.75%
2       34.35%
3       16.95%
4        9.95%

EDITED: I’ve added sample code below as to what I have so far. It only works for periods 1, 2, 3, 5, 9, 10. Maybe someone can help modify it to work for any period. Disclaimer, I’m not a programmer so my coding is bad. Plus, I have no clue as to what I’m doing.

Sub Collapse_Periods()
    Dim aPct As Variant
    Dim aPer As Variant
    aPct = Array(0.106, 0.19, 0.183, 0.145, 0.107, 0.089, 0.065, 0.031, 0.03, 0.054)
    aPer = Array(1, 2, 3, 5, 9, 10)
    For i = 0 To UBound(aPer)
        pm = 10 / aPer(i)
        pct1 = 1
        p = 0
        ttl = 0
        For j = 1 To aPer(i)
            pct = 0
            k = 1
            Do While k <= pm
                pct = pct + aPct(p) * pct1
                pct1 = 1
                p = p + 1
                If k <> pm And k = Int(pm) Then
                    pct1 = (pm - Int(pm)) * j
                    pct = pct + (pct1 * aPct(p))
                    pct1 = 1 - pct1
                End If
                k = k + 1
            Loop
            Debug.Print aPer(i) & " : " & j & " : " & pct
            ttl = ttl + pct
        Next j
        Debug.Print "Total:  " & ttl
    Next i
End Sub

Answer 1