求教这个LINGO代码错在哪？

goldbridge

<>MODEL:<br>TITLE LOCAION PROBLEM;</P>
<>SETS:<br>    demand/1..6/:a,b,d;<br>    supply/1..2/:x,y,e;<br>    link(demand,supply):c;<br>endsets</P>
<>data:<br>!location for the demand;<br>a=1.25,8.75,0.5,5.75,3,7.25;<br>b=1.25,0.75,4.75,5,6.5,7.25;<br>!quanties of the demand and supply;<br>d=3,5,4,7,6,11;<br>e=20,20;<br>enddata</P>
<P>init:<br>!initial location for supply;<br>x=5 2;<br>y=1 7;<br>endinit</P>
<P>!objective function;<br>[obj]min=@sum(link(i,j):c(i,j)*((x(j)-a(i)^2+(y(j)-b(i))^2)^(1/2));</P>
<P>!demand constraints;<br>@for( demand( i): @sum( supply( j):c( i,j))= d( i));</P>
<P>!supply constraints;<br>@for(supply(i)sum(demand(j):c(j,i))&lt;=e(i));</P>
<P>@for(supply(i)free(x);@free(y));<br>end</P>
<P><IMG src="http://free.6to23.com/zzl0609/error.jpg" align=middle border=0></P>
<P>求高手指点！</P>

[此贴子已经被作者于2006-3-4 17:30:05编辑过]

sisk

你的目标函数的括弧不匹配，第一个指数2前面应当加一个括弧“）”。<BR>本人QQ：94339146

goldbridge

<>3Q,</P>
<>看来，LINGO有时不能正确显示错的地方，VC指得比较好</P>