lingo 数模提示model is ill defined,SETS:租赁点坐标及其容量和7:00~8:30,11:0

lingo 数模
提示model is ill defined,
SETS:
租赁点坐标及其容量和7:00~8:30,11:00~12:30,17:30~19:00需求量,初始量,实际量,骑走的车,得到的车;
Sites/S1..S30/ :x,y,sites_capacity,demand1,demand2,demand3,sites_initiation,sites_possess,away,get;
租赁点距离,还车概率,距离与还车概率乘积常数;
Links(sites,sites):distance,return_rate,constant_d_and_r,goto;
ENDSETS
@for(sites:
x05@sum(sites:return_rate(i,j)) =1);
还车距离少于2km且距离不为0;
@for(links:
x05return_rate(i,j) = @if(distance(i,j) #gt# 2 #and# distance(i,j) #ne# 0,0,constant_d_and_r(i,j)/ distance(i,j)));