Home |
Search |
Today's Posts |
#1
Posted to microsoft.public.excel.programming
|
|||
|
|||
Column Combinatorics
Hi all,
instead of reenventing the wheel I turn to this group with my case: assume a single column consisting of 20 cells; now, 11 cells contain the number 1, others are empty. What I'm looking for is an elegant way of elaborating all possible combinations of these 11 pieces as how they can be scattered throughout 20 empty cells. Mind you, this could be done by hand (ahhhhh), but a few combinations could be ommitted simply by mistake, and to accomplish this would be a real drudgery; that's why I'm looking for an algorithm to have this done for me. Any ideas? Mac. |
#2
Posted to microsoft.public.excel.programming
|
|||
|
|||
Column Combinatorics
Mac,
There are =COMBIN(20,11) or 167,960 different ways to group 20 item 11 at a time. Mind you, this could be done by hand (ahhhhh), Sure, if you have a lot of time on your hands.... Better would be to explain what you are trying to do - perhaps you could randomly select 11 items out of the 20? If you really want an algorithm, see below. HTH, Bernie MS Excel MVP Here is some wonderful code from Myrna Larsen. Follow the directions at the top, and you're good to go. 'Maybe, Myrna will post the entire functioning code module ' 'Since you asked, here it is. It is generic, i.e. it isn't written specifically 'for a given population and set size, as yours it. It will do permutations or 'combinations. It uses a recursive routine to generate the subsets, one routine 'for combinations, a different one for permutations. ' 'To use it, you put the letter C or P (for combinations or permutations) in a 'cell. The cell below that contains the number of items in a subset. The cells 'below are a list of the items that make up the population. They could be 'numbers, letters and symbols, or words, etc. ' 'You select the top cell, or the entire range and run the sub. The subsets are 'written to a new sheet in the workbook. Option Explicit Dim vAllItems As Variant Dim Buffer() As String Dim BufferPtr As Long Dim Results As Worksheet Sub ListPermutations() Dim Rng As Range Dim PopSize As Integer Dim SetSize As Integer Dim Which As String Dim N As Double Const BufferSize As Long = 4096 Set Rng = Selection.Columns(1).Cells If Rng.Cells.Count = 1 Then Set Rng = Range(Rng, Rng.End(xlDown)) End If PopSize = Rng.Cells.Count - 2 If PopSize < 2 Then GoTo DataError SetSize = Rng.Cells(2).Value If SetSize PopSize Then GoTo DataError Which = UCase$(Rng.Cells(1).Value) Select Case Which Case "C" N = Application.WorksheetFunction.Combin(PopSize, SetSize) Case "P" N = Application.WorksheetFunction.Permut(PopSize, SetSize) Case Else GoTo DataError End Select If N Cells.Count Then GoTo DataError Application.ScreenUpdating = False Set Results = Worksheets.Add vAllItems = Rng.Offset(2, 0).Resize(PopSize).Value ReDim Buffer(1 To BufferSize) As String BufferPtr = 0 If Which = "C" Then AddCombination PopSize, SetSize Else AddPermutation PopSize, SetSize End If vAllItems = 0 Application.ScreenUpdating = True Exit Sub DataError: If N = 0 Then Which = "Enter your data in a vertical range of at least 4 cells. " _ & String$(2, 10) _ & "Top cell must contain the letter C or P, 2nd cell is the number " _ & "of items in a subset, the cells below are the values from which " _ & "the subset is to be chosen." Else Which = "This requires " & Format$(N, "#,##0") & _ " cells, more than are available on the worksheet!" End If MsgBox Which, vbOKOnly, "DATA ERROR" Exit Sub End Sub Private Sub AddPermutation(Optional PopSize As Integer = 0, _ Optional SetSize As Integer = 0, _ Optional NextMember As Integer = 0) Static iPopSize As Integer Static iSetSize As Integer Static SetMembers() As Integer Static Used() As Integer Dim i As Integer If PopSize < 0 Then iPopSize = PopSize iSetSize = SetSize ReDim SetMembers(1 To iSetSize) As Integer ReDim Used(1 To iPopSize) As Integer NextMember = 1 End If For i = 1 To iPopSize If Used(i) = 0 Then SetMembers(NextMember) = i If NextMember < iSetSize Then Used(i) = True AddPermutation , , NextMember + 1 Used(i) = False Else SavePermutation SetMembers() End If End If Next i If NextMember = 1 Then SavePermutation SetMembers(), True Erase SetMembers Erase Used End If End Sub 'AddPermutation Private Sub AddCombination(Optional PopSize As Integer = 0, _ Optional SetSize As Integer = 0, _ Optional NextMember As Integer = 0, _ Optional NextItem As Integer = 0) Static iPopSize As Integer Static iSetSize As Integer Static SetMembers() As Integer Dim i As Integer If PopSize < 0 Then iPopSize = PopSize iSetSize = SetSize ReDim SetMembers(1 To iSetSize) As Integer NextMember = 1 NextItem = 1 End If For i = NextItem To iPopSize SetMembers(NextMember) = i If NextMember < iSetSize Then AddCombination , , NextMember + 1, i + 1 Else SavePermutation SetMembers() End If Next i If NextMember = 1 Then SavePermutation SetMembers(), True Erase SetMembers End If End Sub 'AddCombination Private Sub SavePermutation(ItemsChosen() As Integer, _ Optional FlushBuffer As Boolean = False) Dim i As Integer, sValue As String Static RowNum As Long, ColNum As Long If RowNum = 0 Then RowNum = 1 If ColNum = 0 Then ColNum = 1 If FlushBuffer = True Or BufferPtr = UBound(Buffer()) Then If BufferPtr 0 Then If (RowNum + BufferPtr - 1) Rows.Count Then RowNum = 1 ColNum = ColNum + 1 If ColNum 256 Then Exit Sub End If Results.Cells(RowNum, ColNum).Resize(BufferPtr, 1).Value _ = Application.WorksheetFunction.Transpose(Buffer()) RowNum = RowNum + BufferPtr End If BufferPtr = 0 If FlushBuffer = True Then Erase Buffer RowNum = 0 ColNum = 0 Exit Sub Else ReDim Buffer(1 To UBound(Buffer)) End If End If 'construct the next set For i = 1 To UBound(ItemsChosen) sValue = sValue & ", " & vAllItems(ItemsChosen(i), 1) Next i 'and save it in the buffer BufferPtr = BufferPtr + 1 Buffer(BufferPtr) = Mid$(sValue, 3) End Sub 'SavePermutation "Mac" wrote in message ... Hi all, instead of reenventing the wheel I turn to this group with my case: assume a single column consisting of 20 cells; now, 11 cells contain the number 1, others are empty. What I'm looking for is an elegant way of elaborating all possible combinations of these 11 pieces as how they can be scattered throughout 20 empty cells. Mind you, this could be done by hand (ahhhhh), but a few combinations could be ommitted simply by mistake, and to accomplish this would be a real drudgery; that's why I'm looking for an algorithm to have this done for me. Any ideas? Mac. |
#3
Posted to microsoft.public.excel.programming
|
|||
|
|||
Column Combinatorics
And if you want to know what the 167,960 combinations are have a look in your
other thread and stick to a single thread. Mike "Mac" wrote: Hi all, instead of reenventing the wheel I turn to this group with my case: assume a single column consisting of 20 cells; now, 11 cells contain the number 1, others are empty. What I'm looking for is an elegant way of elaborating all possible combinations of these 11 pieces as how they can be scattered throughout 20 empty cells. Mind you, this could be done by hand (ahhhhh), but a few combinations could be ommitted simply by mistake, and to accomplish this would be a real drudgery; that's why I'm looking for an algorithm to have this done for me. Any ideas? Mac. |
#4
Posted to microsoft.public.excel.programming
|
|||
|
|||
Column Combinatorics
.. elaborating ..
'msgbox' probably isn't what you want, but you can change that: Const gN = 20, gK = 11 Sub Main() Call Recurse(0, 1, "") ' level, start, string End Sub Sub Recurse(pLevel%, pStart%, pStr$) Dim i1% If pLevel = gK Then ' got gN items MsgBox pStr Exit Sub End If For i1 = pStart To gN + gK - pLevel - 1 Call Recurse(pLevel + 1, i1 + 1, pStr & i1 & " ") Next i1 End Sub ' Dave D-C Mac wrote: Hi all, instead of reenventing the wheel I turn to this group with my case: assume a single column consisting of 20 cells; now, 11 cells contain the number 1, others are empty. What I'm looking for is an elegant way of elaborating all possible combinations of these 11 pieces as how they can be scattered throughout 20 empty cells. Mind you, this could be done by hand (ahhhhh), but a few combinations could be ommitted simply by mistake, and to accomplish this would be a real drudgery; that's why I'm looking for an algorithm to have this done for me. Any ideas? Mac. ----== Posted via Pronews.Com - Unlimited-Unrestricted-Secure Usenet News==---- http://www.pronews.com The #1 Newsgroup Service in the World! 100,000 Newsgroups ---= - Total Privacy via Encryption =--- |
Reply |
Thread Tools | Search this Thread |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Forum | |||
Column Combinatorics | Excel Worksheet Functions | |||
Search for a column based on the column header and then past data from it to another column in another workbook | Excel Programming | |||
Based on a condition in one column, search for a year in another column, and display data from another column in the same row look | Excel Programming | |||
Based on a condition in one column, search for a year in another column, and display data from another column in the same row look | Excel Discussion (Misc queries) | |||
How can i have all alike product codes in column A be matched with like cities in column B and then add the totals that are in column C | Excel Programming |