重心法选址

2单设施重心法选址2.1实验目的掌握单设施重心法选址的原理，能够计算简单选址题目中待选设施的位置；掌握单设施重心选址的算法流程，能够设计类似题目的算法流程，并编写程序。2.2实验过程(1)单设施重心法选址的原理重心法选址模型示意图如图2-1所示。图2-1单设施重心法选址选址示意图求解目标：C-总成本最低其中：fi-序号为i的点的运输费率；Vi-序号为i的点的产量或者销量；di-序号为i的点到待选设施点的相对距离。待选设施位置的计算公式：其中：Xc-重心的X坐标；Yc-重心的Y坐标；Xi-第i个地点X坐标；Yi-第i个地点Y坐标；iiniidVfMinC1niiiiniiiiicdVfdxVfX11)/()/(niiiiniiiiicdVfdyVfY11)/()/()()(22yicixcddYdXiXY?(2)算法流程图，如图2-2所示。图2-2算法流程图2.3实验结果（1）单设施重心法选址程序参数设定及其求解界面如图2-3所示。图2-3单设施重心法选址程序参数设定及其求解界面初始化Xc=0，Yc=0JD=0.001赋值SumCOld=0SumCNew=0Sum1=0Sum2=0Sum3=0计算diSumCOldXc,YcDiSumCNew判断（SumCOld-SumCNew）=JD输出Xc,YcSumCNewj(跌代次数)停止j=j+1是否（2）参数设定及其求解界面变量声明部分（代码）PrivateSubCommand1_Click()IfText1.Text=ThenMsgBoxX-横坐标不允许为空Text1.SetFocusExitSubElseIfIsNumeric(Text1.Text)=FalseThenMsgBoxX-横坐标必须为数值型数据！Text1.Text=Text1.SetFocusExitSubEndIfIfText2.Text=ThenMsgBoxY-纵坐标不允许为空Text2.SetFocusExitSubElseIfIsNumeric(Text2.Text)=FalseThenMsgBoxY-纵坐标必须为数值型数据！Text2.Text=Text2.SetFocusExitSubEndIfIfText3.Text=ThenMsgBox产量或销量不允许为空Text3.SetFocusExitSubElseIfIsNumeric(Text3.Text)=FalseThenMsgBox产量或销量应为数值型数据！Text3.Text=Text3.SetFocusExitSubElseIfVal(Text3.Text)0ThenMsgBox产量或销量应为正数，否则无实际意义！Text3.Text=Text3.SetFocusExitSubEndIfIfText4.Text=ThenMsgBox运输费率不允许为空Text4.SetFocusExitSubElseIfIsNumeric(Text4.Text)=FalseThenMsgBox运输费率应为数值型数据！Text4.Text=Text4.SetFocusExitSubElseIfVal(Text4.Text)0ThenMsgBox运输费率应为正数，否则无实际意义！Text4.Text=Text4.SetFocusExitSubEndIfIfText5.Text=ThenMsgBoxX0-横坐标不允许为空Text5.SetFocusExitSubElseIfIsNumeric(Text5.Text)=FalseThenMsgBoxX0-横坐标必须为数值型数据！Text5.Text=Text5.SetFocusExitSubEndIfIfText6.Text=ThenMsgBoxY0-纵坐标不允许为空Text6.SetFocusExitSubElseIfIsNumeric(Text6.Text)=FalseThenMsgBoxY0-纵坐标必须为数值型数据！Text6.Text=Text6.SetFocusExitSubEndIfIfText7.Text=ThenMsgBox精度不允许为空Text7.SetFocusExitSubElseIfIsNumeric(Text7.Text)=FalseThenMsgBox精度应为数值型数据！Text7.Text=Text7.SetFocusExitSubElseIfVal(Text7.Text)0ThenMsgBox精度应为正数，否则无实际意义！Text7.Text=Text7.SetFocusExitSubEndIfFori=1ToList1.ListCountIfText1.Text=Val(List1.List(i-1))AndText2.Text=Val(List2.List(i-1))ThenMsgBox与第&i&输入坐标值相同，请重新输入Text1.Text=Text2.Text=Text3.Text=Text4.Text=Text1.SetFocusExitSubEndIfNextiList1.AddItemText1.TextList2.AddItemText2.TextList3.AddItemText3.TextList4.AddItemText4.TextText1.Text=Text2.Text=Text3.Text=Text4.Text=Text1.SetFocusIfList1.ListCount=2ThenCommand2.Enabled=TrueEndIfEndSubPrivateSubCommand2_Click()Xc=Val(Text5.Text)Yc=Val(Text6.Text)JD=Val(Text7.Text)DimSumCOAsDoubleDimSumCNAsDoubleDimSum1AsDoubleDimSum2AsDoubleDimSum3AsDoubleForj=1To10000SumCO=0SumCN=0Sum1=0Sum2=0Sum3=0Fori=1ToList1.ListCountdi=Sqr((Xc-Val(List1.List(i-1)))^2+(Yc-Val(List2.List(i-1)))^2)'距离公式SumCO=SumCO+Val(List3.List(i-1))*Val(List4.List(i-1))*diSum1=Sum1+(Val(List1.List(i-1))*Val(List3.List(i-1))*Val(List4.List(i-1)))/diSum2=Sum2+(Val(List2.List(i-1))*Val(List3.List(i-1))*Val(List4.List(i-1)))/diSum3=Sum3+(Val(List3.List(i-1))*Val(List4.List(i-1)))/diNextiXc=Sum1/Sum3Yc=Sum2/Sum3Fori=1ToList1.ListCountdi=Sqr((Xc-Val(List1.List(i-1)))^2+(Yc-Val(List2.List(i-1)))^2)SumCN=SumCN+Val(List3.List(i-1))*Val(List4.List(i-1))*diNextiIf(SumCO-SumCN)=JDThenText8.Text=XcText9.Text=YcText10.Text=SumCNText11.Text=jExitForEndIfNextjEndSubPrivateSubList1_Click()Fori=1ToList1.ListCountIfList1.Selected(i-1)=TrueThenh=InputBox(请输入要改的参数：,参数修正)IfhAndIsNumeric(h)=TrueThenList1.List(i-1)=hElse:MsgBox输入的数据必须为数值型数据EndIfEndIfNextiEndSubPrivateSubList2_Click()Fori=1ToList2.ListCountIfList2.Selected(i-1)=TrueThenh=InputBox(请输入要改的参数：,参数修正)IfhAndIsNumeric(h)=TrueThenList2.List(i-1)=hElse:MsgBox输入的数据必须为数值型数据EndIfEndIfNextiEndSubPrivateSubList3_Click()Fori=1ToList3.ListCountIfList3.Selected(i-1)=TrueThenh=InputBox(请输入要改的参数：,参数修正)IfhAndIsNumeric(h)=TrueAndVal(h)0ThenList3.List(i-1)=hElse:MsgBox输入的数据必须为数值型数据EndIfEndIfNextiEndSubPrivateSubList4_Click()Fori=1ToList4.ListCountIfList4.Selected(i-1)=TrueThenh=InputBox(请输入要改的参数：,参数修正)IfhAndIsNumeric(h)=TrueAndVal(h)0ThenList4.List(i-1)=hElse:MsgBox输入的数据必须为数值型数据EndIfEndIfNextiEndSub(3)单设施重心法选址程序求解结果如图2-4所示。图2-4单设施重心法选址程序求解结果