我的模型是混合型非线性规划，用Lingo求解显示Numerical instability。有20个0、1变量，40个连续变量。下面是我的程序，大家帮忙看看是怎么回事啊（跪谢啊），为什么会出现这种情况呢。（我一直在想是不是我程序编错了。。。）
sets:
total/1..20/:dis,h,em,fm,a,tc,tm,tt,tall,d,ec,eall;
radio/1,2/:ru,w;
link(total,radio):r,p,ratio,t,tmpt;
endsets
min = @sum(total(i):eall(i));
@for(total(i):a(i)*(1-@sum(radio(j):ratio(i,j)))+(1-a(i))*@sum(radio(m):ratio(i,m))=0);
@for(total(i):tall(i)<=12);
@for(radio(j):@sum(total(i):a(i)*r(i,j))<=ru(j));
@for(total(i):@for(radio(j):r(i,j)=(10^3)*w(j)*@log(1+(@if(ratio(i,j),1,0)*p(i,j)*h(j))/(noize+@sum(total(m)|m #ne# i:p(m,j)*h(i)*@if(ratio(m,j),1,0))))/@log(2)/8));
!@for(total(i):@for(radio(j):r(i,j)=(10^3)*w(j)*@log(1+(10*@if(ratio(i,j),1,0)*@log(p(i,j)*h(j)))/(noize+@sum(total(m)|m #ne# i:10*@log(p(m,j)*h(i)*@if(ratio(m,j),1,0)))))/@log(2)/8));
@for(total(i):@for(radio(j):t(i,j)=@if(ratio(i,j),b*ratio(i,j)/r(i,j),0)));
@for(total(i):@for(radio(j):tmpt(i,j)=a(i)*t(i,j)));
@for(total(i):tt(i)=@max(radio(j):tmpt(i,j)));
@for(total(i):tall(i) = a(i)*tc(i) + (1-a(i))*tm(i) + tt(i));
@for(total(i):ec(i)=@sum(radio(j):p(i,j)*t(i,j)));
@for(total(i):eall(i)=a(i)*ec(i) + (1-a(i))*em(i));

@for(total(i):@for(radio(j):@bnd(0,ratio(i,j),1)));
@for(total(i):@bin(a(i)));

data:
noize = -80;
fc = 10;
fm = 0.5000,1.0000,1.0000,0.8000,0.8000,0.5000,0.8000,1.0000,0.8000,0.8000,0.5000,0.8000,0.8000,1.0000,0.8000,0.8000,1.0000,0.5000,1.0000,1.0000;
dis = 15.0208,27.9390,12.6232,9.8247,20.3638,23.2139,12.1137,24.0493,14.6440,19.4403,26.6725,11.0368,25.6927,30.9869,13.3209,10.2519,14.3367,30.8337,15.6178,21.9266;
enddata
calc:
b = 420;
c = 1000*(10^(-3));
ru(1) = 40*10^3;
ru(2) = 80*10^3;
w(1) = 20;
w(2) = 30;
@for(total(i):d(i)=6);
@for(total(i):p(i,1)=80);
@for(total(i):p(i,2)=100);
@for(total(i):h(i) = @pow(dis(i),-4));
@for(total(i):em(i) = c*(10^3)*(10^3)*(10^(-11))*(@pow(fm(i)*(10^3),2)));
@for(total(i):tc(i)=c/fc);  
@for(total(i):tm(i)=c/fm(i));
endcalc