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发表于 2004-5-4 20:25:23
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< 0cm 0cm 0pt"><FONT face="Times New Roman">LINGO</FONT>使用简介:</P>< 0cm 0cm 0pt">例:<FONT face="Times New Roman">LINGO</FONT>中问题的一个典型模型如下:<FONT face="Times New Roman"> </FONT>(<FONT face="Times New Roman">SAILCO</FONT>)</P>< 0cm 0cm 0pt"><p><FONT face="Times New Roman"> </FONT></p></P><P 0cm 0cm 0pt"><FONT face="Times New Roman"> MODEL:</FONT></P><P 0cm 0cm 0pt"><FONT face="Times New Roman"> 1]SETS:</FONT></P><P 0cm 0cm 0pt"><FONT face="Times New Roman"> 2]QUARTERS/Q1,Q2,Q3,Q4/:TIME,DEM,RP,OP,INV;</FONT></P><P 0cm 0cm 0pt"><FONT face="Times New Roman"> 3]ENDSETS</FONT></P><P 0cm 0cm 0pt"><FONT face="Times New Roman"> 4]MIN=@SUM(QUARTERS:400*RP+450*OP+20*INV);</FONT></P><P 0cm 0cm 0pt"><FONT face="Times New Roman"> 5]@FOR(QUARTERS(I):RP(I)<40);</FONT></P><P 0cm 0cm 0pt"><FONT face="Times New Roman"> 6]@FOR(QUARTERS(I)|TIME(I)#GT#1:</FONT></P><P 0cm 0cm 0pt"><FONT face="Times New Roman"> 7]INV(I)=INV(I-1)+RP(I)+OP(I)-DEM(I););</FONT></P><P 0cm 0cm 0pt"><FONT face="Times New Roman"> 8]INV(1)=10+RP(1)+OP(1)-DEM(1);</FONT></P><P 0cm 0cm 0pt"><FONT face="Times New Roman"> 9]DATA:</FONT></P><P 0cm 0cm 0pt"><FONT face="Times New Roman"> 10]DEM=40,60,75,25;</FONT></P><P 0cm 0cm 0pt"><FONT face="Times New Roman"> 11]TIME=1,2,3,4;</FONT></P><P 0cm 0cm 0pt"><FONT face="Times New Roman"> 12]ENDDATA</FONT></P><P 0cm 0cm 0pt"><FONT face="Times New Roman"> END</FONT></P><P 0cm 0cm 0pt"><p><FONT face="Times New Roman"> </FONT></p></P><P 0cm 0cm 0pt">从上述<FONT face="Times New Roman">MODEL</FONT>中,我们可看到整个模型分为三大部分:</P><P 0cm 0cm 0pt"><FONT face="Times New Roman">1</FONT>)<FONT face="Times New Roman">SETS</FONT>──<FONT face="Times New Roman">ENDSETS</FONT></P><P 0cm 0cm 0pt; TEXT-INDENT: 21pt">其中定义了模型中用到的各个集合,包括变量,数组,变量的特征量等。如上例中定义了四个<FONT face="Times New Roman">quarters1,Q2,Q3,Q4. </FONT>其中每个<FONT face="Times New Roman">quarter</FONT>都有<FONT face="Times New Roman">TIME,DEM,RP,OP,INV</FONT>这样的特征量。一旦这样的定义建立起来,实际上<FONT face="Times New Roman">quarter</FONT>的数量可以为<FONT face="Times New Roman">40</FONT>,<FONT face="Times New Roman">400</FONT>,或许<FONT face="Times New Roman">4000</FONT>,它们仍都有<FONT face="Times New Roman">TIME,DEM,RP,OP,INV</FONT>这样的特征量。这些量的具体数值可在<FONT face="Times New Roman">DATA</FONT>──<FONT face="Times New Roman">ENDDATA</FONT>这部分输入。</P><P 0cm 0cm 0pt"><p><FONT face="Times New Roman"> </FONT></p></P><P 0cm 0cm 0pt"><FONT face="Times New Roman">2</FONT>)中间部分:</P><P 0cm 0cm 0pt; TEXT-INDENT: 21pt">这部分实际上定义了目标函数,约束条件等。</P><P 0cm 0cm 0pt"><FONT face="Times New Roman"> </FONT>如上例中:第<FONT face="Times New Roman">4</FONT>行定义了目标函数为<FONT face="Times New Roman">MIN=...</FONT>,其中<FONT face="Times New Roman">@SUM(quarters: ... 400*RP...)</FONT>表示对所有的<FONT face="Times New Roman"> quarters</FONT>计算<FONT face="Times New Roman">400*RP+450*OP+20*INV</FONT>并求和。<FONT face="Times New Roman"> </FONT>注意,如此定义的目标函数与<FONT face="Times New Roman">quarters</FONT>的数目是<FONT face="Times New Roman"> 4, 40, 400, </FONT>或<FONT face="Times New Roman"> 4000</FONT>并无具体的关系。</P><P 0cm 0cm 0pt; TEXT-INDENT: 21pt">第<FONT face="Times New Roman">5</FONT>行表示对每个<FONT face="Times New Roman">quarter, RP</FONT>不能超过<FONT face="Times New Roman">40 . </FONT></P><P 0cm 0cm 0pt"><FONT face="Times New Roman"> </FONT>第<FONT face="Times New Roman">6</FONT>,<FONT face="Times New Roman">7</FONT>行也是对每个<FONT face="Times New Roman">quarter</FONT>中具体约束的定义。</P><P 0cm 0cm 0pt">注意:</P><P 0cm 0cm 0pt"><FONT face="Times New Roman"> </FONT>与<FONT face="Times New Roman">LINDO</FONT>不同的是变量可以放在约束条件的右端(同时数字也可放在约束条件的左端)。<FONT face="Times New Roman"> .</FONT></P><P 0cm 0cm 0pt"><p><FONT face="Times New Roman"> </FONT></p></P><P 0cm 0cm 0pt"><FONT face="Times New Roman">3</FONT>)<FONT face="Times New Roman">DATA</FONT>──<FONT face="Times New Roman">ENDDATA</FONT></P><P 0cm 0cm 0pt; TEXT-INDENT: 21pt">行<FONT face="Times New Roman">9-12</FONT>的作用在于输入必要的数据。</P><P 0cm 0cm 0pt; TEXT-INDENT: 21pt">这部分要以<FONT face="Times New Roman"> DATA: </FONT>开始,<FONT face="Times New Roman"> </FONT>以<FONT face="Times New Roman"> ENDDATA</FONT>结束。</P><P 0cm 0cm 0pt"><p><FONT face="Times New Roman"> </FONT></p></P><P 0cm 0cm 0pt"><FONT face="Times New Roman"> </FONT>实际上,<FONT face="Times New Roman">LINGO</FONT>的问题也可以类似<FONT face="Times New Roman">LINDO</FONT>的方式输入,如上述<FONT face="Times New Roman">SAILCO</FONT>问题可转化为如下形式:</P><P 0cm 0cm 0pt"><FONT face="Times New Roman"> MIN 400 RP(Q1 + 450 OP(Q1 + 20 INV(Q1 + 400 RP(Q2 + 450 OP(Q2 + 20 INV(Q2</FONT></P><P 0cm 0cm 0pt"><FONT face="Times New Roman"> + 400 RP(Q3 + 450 OP(Q3 + 20 INV(Q3 + 400 RP(Q4 + 450 OP(Q4</FONT></P><P 0cm 0cm 0pt"><FONT face="Times New Roman"> + 20 INV(Q4</FONT></P><P 0cm 0cm 0pt"><FONT face="Times New Roman"> SUBJECT TO</FONT></P><P 0cm 0cm 0pt"><FONT face="Times New Roman"> 2) RP(Q1 <= 40</FONT></P><P 0cm 0cm 0pt"><FONT face="Times New Roman"> 3) RP(Q2 <= 40</FONT></P><P 0cm 0cm 0pt"><FONT face="Times New Roman"> 4) RP(Q3 <= 40</FONT></P><P 0cm 0cm 0pt"><FONT face="Times New Roman"> 5) RP(Q4 <= 40</FONT></P><P 0cm 0cm 0pt"><FONT face="Times New Roman"> 6)- INV(Q1 - RP(Q2 - OP(Q2 + INV(Q2 = - 60</FONT></P><P 0cm 0cm 0pt"><FONT face="Times New Roman"> 7)- INV(Q2 - RP(Q3 - OP(Q3 + INV(Q3 = - 75</FONT></P><P 0cm 0cm 0pt"><FONT face="Times New Roman"> 8)- INV(Q3 - RP(Q4 - OP(Q4 + INV(Q4 = - 25</FONT></P><P 0cm 0cm 0pt"><FONT face="Times New Roman"> 9)- RP(Q1 - OP(Q1 + INV(Q1 = - 30</FONT></P><P 0cm 0cm 0pt"><FONT face="Times New Roman"> END</FONT></P><P 0cm 0cm 0pt"><p><FONT face="Times New Roman"> </FONT></p></P><P 0cm 0cm 0pt">用<FONT face="Times New Roman">GO</FONT>命令求解结果如下:</P><P 0cm 0cm 0pt"><p><FONT face="Times New Roman"> </FONT></p></P><P 0cm 0cm 0pt"><FONT face="Times New Roman"> LP OPTIMUM FOUND AT STEP 7</FONT></P><P 0cm 0cm 0pt"><FONT face="Times New Roman"> OBJECTIVE VALUE = 78450.0000 </FONT></P><P 0cm 0cm 0pt"><p><FONT face="Times New Roman"> </FONT></p></P><P 0cm 0cm 0pt"><FONT face="Times New Roman"> VARIABLE VALUE REDUCED COST</FONT></P><P 0cm 0cm 0pt"><FONT face="Times New Roman"> TIME( Q1) 1.000000 .0000000 </FONT></P><P 0cm 0cm 0pt"><FONT face="Times New Roman"> TIME( Q2) 2.000000 .0000000 </FONT></P><P 0cm 0cm 0pt"><FONT face="Times New Roman"> TIME( Q3) 3.000000 .0000000 </FONT></P><P 0cm 0cm 0pt"><FONT face="Times New Roman"> TIME( Q4) 4.000000 .0000000 </FONT></P><P 0cm 0cm 0pt"><FONT face="Times New Roman"> DEM( Q1) 40.00000 .0000000 </FONT></P><P 0cm 0cm 0pt"><FONT face="Times New Roman"> DEM( Q2) 60.00000 .0000000 </FONT></P><P 0cm 0cm 0pt"><FONT face="Times New Roman"> DEM( Q3) 75.00000 .0000000 </FONT></P><P 0cm 0cm 0pt"><FONT face="Times New Roman"> DEM( Q4) 25.00000 .0000000 </FONT></P><P 0cm 0cm 0pt"><FONT face="Times New Roman"> RP( Q1) 40.00000 .0000000 </FONT></P><P 0cm 0cm 0pt"><FONT face="Times New Roman"> RP( Q2) 40.00000 .0000000 </FONT></P><P 0cm 0cm 0pt"><FONT face="Times New Roman"> RP( Q3) 40.00000 .0000000 </FONT></P><P 0cm 0cm 0pt"><FONT face="Times New Roman"> RP( Q4) 25.00000 .0000000 </FONT></P><P 0cm 0cm 0pt"><FONT face="Times New Roman"> OP( Q1) .0000000 20.00000 </FONT></P><P 0cm 0cm 0pt"><FONT face="Times New Roman"> OP( Q2) 10.00000 .0000000 </FONT></P><P 0cm 0cm 0pt"><FONT face="Times New Roman"> OP( Q3) 35.00000 .0000000 </FONT></P><P 0cm 0cm 0pt"><FONT face="Times New Roman"> OP( Q4) .0000000 50.00000 </FONT></P><P 0cm 0cm 0pt"><FONT face="Times New Roman"> INV( Q1) 10.00000 .0000000 </FONT></P><P 0cm 0cm 0pt"><FONT face="Times New Roman"> INV( Q2) .0000000 20.00000 </FONT></P><P 0cm 0cm 0pt"><FONT face="Times New Roman"> INV( Q3) .0000000 70.00000 </FONT></P><P 0cm 0cm 0pt"><FONT face="Times New Roman"> INV( Q4) .0000000 420.0000 </FONT></P><P 0cm 0cm 0pt"><p><FONT face="Times New Roman"> </FONT></p></P><P 0cm 0cm 0pt"><FONT face="Times New Roman"> ROW SLACK OR SURPLUS DUAL PRICE </FONT></P><P 0cm 0cm 0pt"><FONT face="Times New Roman"> 1 78450.00 1.000000 </FONT></P><P 0cm 0cm 0pt"><FONT face="Times New Roman"> 2 .0000000 30.00000 </FONT></P><P 0cm 0cm 0pt"><FONT face="Times New Roman"> 3 .0000000 50.00000 </FONT></P><P 0cm 0cm 0pt"><FONT face="Times New Roman"> 4 .0000000 50.00000 </FONT></P><P 0cm 0cm 0pt"><FONT face="Times New Roman"> 5 15.00000 .0000000 </FONT></P><P 0cm 0cm 0pt"><FONT face="Times New Roman"> 6 .0000000 450.0000 </FONT></P><P 0cm 0cm 0pt"><FONT face="Times New Roman"> 7 .0000000 450.0000 </FONT></P><P 0cm 0cm 0pt"><FONT face="Times New Roman"> 8 .0000000 400.0000 </FONT></P><P 0cm 0cm 0pt"><FONT face="Times New Roman"> 9 .0000000 430.0000 </FONT></P><P 0cm 0cm 0pt"><p><FONT face="Times New Roman"> </FONT></p></P> |
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