[英]Optimizing Big Data Comparison Using For Loops
好的,这是交易人员。 我有two text files
。 每个包含500
行(句子)。
我已将它们加载到memory
形成自己的数组(数据类型:字符串)。 我们将array A & B
命名为array A & B
接下来,我得到array A
的first sentence
,使用SPACE
作为分隔符将其拆分为另一个array C
,以便得到单词。
然后对于array B
每个句子,我再次使用SPACE
作为分隔符将其分成array D
以获得单词,并将array C
中的每个单词与array D
每个单词进行比较,计算两个句子之间的百分比匹配。
我计算在第一个句子的平均百分比匹配array A
针对所有的句子array B
。
然后我将它存储到一个Array E
,其中包含array A
所有句子及其平均匹配百分比。
对于数组A中的每个标题,我用上面的first sentence
做我的工作。
问题是,处理阵列A中的每个标题大约需要15秒。无论如何,我可以优化这个时间来加快速度吗?
硬件: AMD Phenom I 32位四核
码:
Imports System.IO
Imports System.Object
Imports System.Xml
Imports System.Text.RegularExpressions
Module Module1
Sub Main()
'Important File Paths
Dim titlesFilePath As String = Environment.CurrentDirectory & "\titles.txt"
Dim xmlTitlesFilePath As String = Environment.CurrentDirectory & "\extractedTitles.txt"
Dim stopWordsFilePath As String = Environment.CurrentDirectory & "\stopWords.txt"
'Import Important Data From Files -> Memory
Dim titles As Array = FileToArray(titlesFilePath)
Dim stopWords As Array = FileToArray(stopWordsFilePath)
Dim xmlDataUnprocessed As Array = FileToArray(xmlTitlesFilePath)
'Delimters To Filter Titles For
Dim userDefinedDelimeters(4, 1)
userDefinedDelimeters(0, 0) = "-"
userDefinedDelimeters(0, 1) = " "
userDefinedDelimeters(1, 0) = ","
userDefinedDelimeters(1, 1) = " "
userDefinedDelimeters(2, 0) = "—"
userDefinedDelimeters(2, 1) = " "
userDefinedDelimeters(3, 0) = "'s"
userDefinedDelimeters(3, 1) = ""
userDefinedDelimeters(4, 0) = "'"
userDefinedDelimeters(4, 1) = " "
'Declare Important Variables
Dim xmlData(xmlDataUnprocessed.Length / 2, 1)
Dim xmlTurn = 0
Dim xmlDataCount = 0
'Create Feed Title/URL Array
For i = 0 To (xmlDataUnprocessed.Length - 1)
If xmlTurn = 0 Then
xmlData(xmlDataCount, 0) = xmlDataUnprocessed(i)
xmlTurn = 1
Else
xmlData(xmlDataCount, 1) = xmlDataUnprocessed(i)
xmlTurn = 0
xmlDataCount += 1
End If
Next
'CPU-Intensive Stuff Occurs
Dim xmlTitle As String
Dim xmlTitleWords As Array
Dim savedTitleWords As Array
Dim titleResults(xmlData.GetUpperBound(0) - 1, 1)
Dim titlePercentageMatch As Integer
Dim numberOfTitlesMatched As Integer
For i = 0 To xmlData.GetUpperBound(0) - 1
Console.WriteLine("Working On Title No. " & i & " Out Of " & xmlData.GetUpperBound(0) - 1)
titlePercentageMatch = 0
numberOfTitlesMatched = 0
xmlTitle = xmlData(i, 0)
xmlTitle = processTitle(stopWords, userDefinedDelimeters, xmlTitle)
xmlTitleWords = xmlTitle.Split(" ")
For Each title In titles
title = processTitle(stopWords, userDefinedDelimeters, title)
savedTitleWords = title.split(" ")
Dim compareResult = compareTitle(xmlTitleWords, savedTitleWords)
If compareResult > 0 Then
titlePercentageMatch += compareResult
numberOfTitlesMatched += 1
End If
Next
titleResults(i, 0) = xmlData(i, 0)
titleResults(i, 1) = (titlePercentageMatch / numberOfTitlesMatched)
Next
For i = 0 To titleResults.GetUpperBound(0) - 1
Console.WriteLine(titleResults(i, 0) & " ---> " & titleResults(i, 1) & vbCrLf)
Next
Console.Read()
End Sub
Function compareTitle(ByRef xmlTitleWords As Array, ByRef savedTitleWords As Array)
Dim NumberOfMatches = 0
For Each xmlWord In xmlTitleWords
For Each savedWord In savedTitleWords
If (xmlWord.ToString.ToLower = savedWord.ToString.ToLower) Then
NumberOfMatches += 1
End If
Next
Next
Return ((NumberOfMatches / xmlTitleWords.Length) * 100)
End Function
Function processTitle(ByRef stopWordArray As Array, ByRef delimArray As Array, ByVal title As String)
title = removeStopWords(stopWordArray, title)
title = removeDelims(delimArray, title)
Return title
End Function
Function removeStopWords(ByRef stopWordsArray As Array, ByVal sentence As String)
For i = 0 To stopWordsArray.Length - 1
If sentence.ToLower.Contains(" " & stopWordsArray(i).ToString.ToLower & " ") = True Then
sentence = Microsoft.VisualBasic.Strings.Replace(sentence, " " & stopWordsArray(i) & " ", " ", 1, -1, Constants.vbTextCompare)
'ElseIf sentence.ToLower.Contains(stopWordsArray(i).ToString.ToLower & " ") = True Then
'sentence = Microsoft.VisualBasic.Strings.Replace(sentence, stopWordsArray(i) & " ", "", 1, -1, Constants.vbTextCompare)
End If
sentence = Regex.Replace(sentence, "\s+", " ")
Dim Words = sentence.ToLower.Split(" ")
If Words(0).ToString.ToLower & " " = stopWordsArray(i).ToString.ToLower & " " Then
sentence = sentence.Remove(0, stopWordsArray(i).ToString.ToLower.Length + 1)
End If
Words = sentence.ToLower.Split(" ")
Dim LastWord = Words(Words.Length - 1)
'Console.WriteLine(LastWord & "++")
If " " & LastWord.ToString.ToLower = " " & stopWordsArray(i).ToString.ToLower Then
sentence = sentence.Remove(sentence.Length - 1 - LastWord.Length, stopWordsArray(i).ToString.ToLower.Length + 1)
End If
Next
sentence = Regex.Replace(sentence, "\s+", " ")
Return sentence
End Function
Function removeDelims(ByRef delimArray As Array, ByVal sentence As String)
For i = 0 To delimArray.GetUpperBound(0) - 1
sentence = sentence.Replace(delimArray(i, 0), delimArray(i, 1))
Next
sentence = Regex.Replace(sentence, "\s+", " ")
Return sentence
End Function
Function FileToArray(ByVal filePath As String) As String()
Dim content As String
Dim lines As New ArrayList
Dim sr As System.IO.StreamReader
' read the file's lines into an ArrayList
Try
sr = New System.IO.StreamReader(filePath)
Do While sr.Peek() >= 0
lines.Add(sr.ReadLine())
Loop
Finally
If Not sr Is Nothing Then sr.Close()
End Try
' convert from ArrayList to a String array
Return CType(lines.ToArray(GetType(String)), String())
End Function
End Module
编辑:我希望它不会太混乱。 对于那个很抱歉! 编辑2:提供酱:P
你的基本算法是N * M * A 2
如果您有500 * 500 * 5 2,那么您将推动6,250,000个不区分大小写的字符串比较。 但那就是你所做的一切。 你的内部循环通过外循环的长度为每个title
调用processTitle
。 它不需要那样做。
你可以做的是有一个预处理步骤,用表示该单词的整数(符号)替换每个单词。 为此,您将使用字典查找符号,如果没有,则分配新的唯一符号(例如,保留整数计数器并使用下一个值)。
然后,您的主处理循环将与之前的类似,但您需要进行整数比较(更快)。 实际上,您希望此处理步骤仅进行比较和统计信息收集。 其他一切都应该搬出去。
保持预处理步骤。
并行化您的处理步骤。 一种方法是使用Parallel.For()作为最外层循环: Parallel.For(0, xmlData.GetUpperBound(0) - 1, Sub(i) ... End Sub)
其中action是你的循环体从上面。 TPL可能会很好地平衡负载(均匀地使用4个内核)。
另一种方法是使用任务并行库来启动对1/4数据进行操作的任务。 然后开始使用结果的延续。
一次只读取array B
到存储器,然后逐行读取array A
适用时使用StringBuilder而不是string。
另外,看看你是否可以使用并行处理,即:任务。
至于距离,匹配算法,你没有提到它是什么以及它是如何做的。 很难说出来。
你用一些东西放慢了自己的速度......
If (xmlWord.ToString.ToLower = savedWord.ToString.ToLower) Then
为什么不把所有内容改成小写,甚至将它放入阵列?
title = processTitle(stopWords, userDefinedDelimeters, title)
为什么不把它加载到数组之前呢?
提前完成所有处理,然后单独进行比较。
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