算法的内存和执行时间减少

时间:2012-11-02 08:49:25

标签: algorithm vba memory excel-vba excel

我被要求再次提出这个问题,并在一个不同的背景下。这是上一篇文章:

Filtering in VBA after finding combinations

我想用100个不同的变量来实现这个代码,而不会让excel耗尽内存并显着缩短执行时间。

以下代码的问题是,如果我有100个框,excel将在“结果(0到2 ^ NumFields - 2)”行中耗尽内存(该代码适用于< 10个框)

这是我的意见:

3   A   B   C   D   E ...
7.7 3   1   1   1   2 ...
5.5 2   1   2   3   3 ...

这是代码:

Function stackBox()
    Dim ws As Worksheet
    Dim width As Long
    Dim height As Long
    Dim numOfBox As Long
    Dim optionsA() As Variant
    Dim results() As Variant
    Dim str As String
    Dim outputArray As Variant
    Dim i As Long, j As Long
    Dim currentSymbol As String
    '------------------------------------new part----------------------------------------------
    Dim maxHeight As Double
    Dim maxWeight As Double
    Dim heightarray As Variant
    Dim weightarray As Variant
    Dim totalHeight As Double
    Dim totalWeight As Double
    '------------------------------------new part----------------------------------------------

    Set ws = Worksheets("Sheet1")
    With ws
        'clear last time's output
        height = .Cells(.Rows.Count, 1).End(xlUp).row
        If height > 3 Then
            .Range(.Cells(4, 1), .Cells(height, 1)).ClearContents
        End If

        numOfBox = .Cells(1, 1).Value
        width = .Cells(1, .Columns.Count).End(xlToLeft).Column
        If width < 2 Then
            MsgBox "Error: There's no item, please fill your item in Cell B1,C1,..."
            Exit Function
        End If


        '------------------------------------new part----------------------------------------------
        maxHeight = .Cells(2, 1).Value
        maxWeight = .Cells(3, 1).Value
        ReDim heightarray(1 To 1, 1 To width - 1)
        ReDim weightarray(1 To 1, 1 To width - 1)
        heightarray = .Range(.Cells(2, 2), .Cells(2, width)).Value
        weightarray = .Range(.Cells(3, 2), .Cells(3, width)).Value
        '------------------------------------new part----------------------------------------------

        ReDim optionsA(0 To width - 2)
        For i = 0 To width - 2
            optionsA(i) = .Cells(1, i + 2).Value
        Next i

        GenerateCombinations optionsA, results, numOfBox


        ' copy the result to sheet only once
        ReDim outputArray(1 To UBound(results, 1) - LBound(results, 1) + 1, 1 To 1)
        Count = 0
        For i = LBound(results, 1) To UBound(results, 1)
            If Not IsEmpty(results(i)) Then
                'rowNum = rowNum + 1
                str = ""
                totalHeight = 0#
                totalWeight = 0#
                For j = LBound(results(i), 1) To UBound(results(i), 1)
                    currentSymbol = results(i)(j)

                    str = str & currentSymbol 'results(i)(j) is the SYMBOL e.g. A, B, C

                    'look up box's height and weight , increment the totalHeight/totalWeight
                    updateParam currentSymbol, optionsA, heightarray, weightarray, totalHeight, totalWeight

                Next j
                If totalHeight < maxHeight And totalWeight < maxWeight Then
                    Count = Count + 1
                    outputArray(Count, 1) = str
                End If

            '.Cells(rowNum, 1).Value = str
            End If
        Next i
        .Range(.Cells(4, 1), .Cells(UBound(outputArray, 1) + 3, 1)).Value = outputArray
    End With

End Function

Sub updateParam(ByRef targetSymbol As String, ByRef symbolArray As Variant, ByRef heightarray As Variant, ByRef weightarray As Variant, ByRef totalHeight As Double, ByRef totalWeight As Double)
Dim i As Long
Dim index As Long
index = -1
For i = LBound(symbolArray, 1) To UBound(symbolArray, 1)
    If targetSymbol = symbolArray(i) Then
        index = i
        Exit For
    End If
Next i


If index <> -1 Then
    totalHeight = totalHeight + heightarray(1, index + 1)
    totalWeight = totalWeight + weightarray(1, index + 1)
End If
End Sub

Sub GenerateCombinations(ByRef AllFields() As Variant, _
                                             ByRef Result() As Variant, ByVal numOfBox As Long)

  Dim InxResultCrnt As Integer
  Dim InxField As Integer
  Dim InxResult As Integer
  Dim i As Integer
  Dim NumFields As Integer
  Dim Powers() As Integer
  Dim ResultCrnt() As String

  NumFields = UBound(AllFields) - LBound(AllFields) + 1

  ReDim Result(0 To 2 ^ NumFields - 2)  ' one entry per combination
  ReDim Powers(0 To NumFields - 1)          ' one entry per field name

  ' Generate powers used for extracting bits from InxResult
  For InxField = 0 To NumFields - 1
    Powers(InxField) = 2 ^ InxField
  Next

 For InxResult = 0 To 2 ^ NumFields - 2
    ' Size ResultCrnt to the max number of fields per combination
    ' Build this loop's combination in ResultCrnt

    ReDim ResultCrnt(0 To NumFields - 1)
    InxResultCrnt = -1
    For InxField = 0 To NumFields - 1
      If ((InxResult + 1) And Powers(InxField)) <> 0 Then
        ' This field required in this combination
        InxResultCrnt = InxResultCrnt + 1
        ResultCrnt(InxResultCrnt) = AllFields(InxField)
      End If
    Next

    If InxResultCrnt = 0 Then
        Debug.Print "testing"
    End If
    'additional logic here
    If InxResultCrnt >= numOfBox Then
        Result(InxResult) = Empty

    Else
         ' Discard unused trailing entries
        ReDim Preserve ResultCrnt(0 To InxResultCrnt)
        ' Store this loop's combination in return array
        Result(InxResult) = ResultCrnt
    End If

  Next

End Sub

1 个答案:

答案 0 :(得分:1)

这是一个版本,可以完成变体数组中的所有繁重任务

(基于This Answer Joubarc的答案的组合逻辑

这在100个方框的样本数据集上运行,其中包含&gt;返回40,000,并且&lt; 1秒

注意:

  1. 如果最大盒子数增加(例如4比100:约13s),执行时间会迅速上升
  2. 如果返回的结果数超过65535,则将数组转置到工作表中的代码失败(sub的最后一行)如果需要处理这可能会导致结果,则需要更改结果返回的方式片

  3. Sub Demo()
        Dim rNames As Range
        Dim rHeights As Range
        Dim rWeights As Range
    
        Dim aNames As Variant
        Dim aHeights As Variant
        Dim aWeights As Variant
    
        Dim MaxNum As Long
        Dim MaxHeight As Double
        Dim MaxWeight As Double
    
        ' *** replace these six line with your data ranges
        Set rNames = Range([F5], [F5].End(xlToRight))
        Set rHeights = rNames.Offset(1, 0)
        Set rWeights = rNames.Offset(2, 0)
        MaxNum = [C5]
        MaxHeight = [C6]
        MaxWeight = [C7]
    
        aNames = rNames
        aHeights = rHeights
        aWeights = rWeights
    
        Dim Result() As Variant
        Dim n As Long, m As Long
        Dim i As Long, j As Long
        Dim iRes As Long
        Dim res As String
        Dim TestCombin() As Long
        Dim TestWeight As Double
        Dim TestHeight As Double
        Dim idx() As Long
    
        ' Number of boxes
        ReDim TestCombin(0 To MaxNum - 1)
        n = UBound(aNames, 2) - LBound(aNames, 2) + 1
    
        ' estimate size of result array = number of possible combinations
        For m = 1 To MaxNum
            i = i + Application.WorksheetFunction.Combin(n, m)
        Next
        ReDim Result(1 To 3, 1 To i)
    
        ' allow for from 1 to MaxNum of boxes
        iRes = 1
        For m = 1 To MaxNum
            ReDim idx(0 To m - 1)
            For i = 0 To m - 1
                idx(i) = i
            Next i
    
            Do
                'Test current combination
                res = ""
                TestWeight = 0#
                TestHeight = 0#
                For j = 0 To m - 1
                    'Debug.Print aNames(1, idx(j) + 1);
                    res = res & aNames(1, idx(j) + 1)
                    TestWeight = TestWeight + aWeights(1, idx(j) + 1)
                    TestHeight = TestHeight + aHeights(1, idx(j) + 1)
                Next j
                'Debug.Print
                If TestWeight <= MaxWeight And TestHeight <= MaxHeight Then
                    Result(1, iRes) = res
                    ' optional, include actual Height and Weight in result
                    Result(2, iRes) = TestHeight
                    Result(3, iRes) = TestWeight
                    iRes = iRes + 1
                End If
    
                ' Locate last non-max index
                i = m - 1
                While (idx(i) = n - m + i)
                    i = i - 1
                    If i < 0 Then
                        'All indexes have reached their max, so we're done
                        Exit Do
                    End If
                Wend
    
                'Increase it and populate the following indexes accordingly
                idx(i) = idx(i) + 1
                For j = i To m - 1
                    idx(j) = idx(i) + j - i
                Next j
            Loop
        Next
    
        ' Return Result to sheet    
        Dim rng As Range
        ReDim Preserve Result(1 To 3, 1 To iRes)
    
        ' *** Adjust returnm range to suit
        Set rng = [E10].Resize(UBound(Result, 2), UBound(Result, 1))
        rng = Application.Transpose(Result)
    End Sub