help with emp needed!

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yann buydens

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Feb 6, 2012, 1:21:26 PM2/6/12
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Hello,

I am a graduate student from belgium and I am trying to solve a
bilevel optimization problem using emp.

I get the following error:

**** ERRORS/WARNINGS IN VARIABLE objin1
1 error(s): BILEVEL: follower obj has no entry in follower
equations

I am a beginner in gams and totally new with emp. This is probably a
very simple mistake but I am at a loss.

What could this mean? what should I look out for?


I have included the code here:

$ A leader-followers game with a cournot game for the followers

$ontext

I am trying to solve the following problem:

maximize{q} E q (sum of the cost of the followers) % maximize the
expected value of system cost based on a set of probabilities q
defined with the constraints


s.t sum of q = 1
-q(S)+pbase(S)/(1-alpha) =G= 0
...



$offtext

set player /p1*p2/
S /s1*s4/
;

parameter I(player) /p1 10, p2 15/

parameter A /100/

parameter B/60/

parameter pbase(S) /s1 0.25, s2 0.25, s3 0.25, s4 0.25/

parameter alpha /0.5/

table c(S,player)
p1 p2
s1 2 3
s2 3 2
s3 4 5
s4 1 1

;



variables systcost(S)
ytot(S)
price(S)
objout
objin1
objin2

;



positive variables x(player)
y(player,S)
q(S)

;


equations defout

defsystcost(S)
defytot(S)
defprice(S)
constraintq(S)
sumone

defin1
constraint1(S)

defin2
constraint2(S)



;

defout.. objout =E= sum(S,q(S)*systcost(S)) ;

defsystcost(S).. systcost(S) =E=
sum(player,c(S,player)*y(player,S))-price(S)*ytot(S);

defytot(S).. ytot(S)=E=sum(player,y(player,S));

defprice(S).. price(S) =E= A-B*ytot(S);

sumone.. sum(S,q(S)) =E= 1;

constraintq(S).. -q(S)+pbase(S)/(1-alpha) =G= 0;




defin1.. objin1 =E= I("p1")*x("p1")+ sum(S,q(S)*(-
price(S)*y("p1",S)+c(S,"p1")*y("p1",S)));

constraint1(S).. x("p1") =G= y("p1",S);


defin2.. objin2 =E= I("p2")*x("p2")+ sum(S,q(S)*(-
price(S)*y("p2",S)+c(S,"p2")*y("p2",S)));

constraint2(S).. x("p2") =G= y("p2",S);


model endorisk / all /;

$onecho > "%emp.info%"
bilevel q
min objin1 x("p1") y("p1",S) defin1 constraint1(S)
min objin2 x("p2") y("p2",S) defin2 constraint2(S)
$offecho



solve endorisk us emp min objout;


yann buydens

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Feb 8, 2012, 4:49:01 AM2/8/12
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problem solved

胡辉

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Feb 10, 2012, 8:17:27 PM2/10/12
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Hi,
 I tried to solve your model, problem is as below:
EMP syntax error: key expected: is y (item 4 on line 2) but instance not in var
                                                                       iable rim
--- EMP Summary  (errors=2)
    Adjusted Constraint = 0
    Flipped Constraints = 0
    Dual Variable Maps  = 0
    Dual Equation Maps  = 0
    VI Functions        = 0
    Equilibrium Agent   = 0
    Bilevel Followers   = 1
    Disjunctions        = 0
    Logical Constraints = 0
***
*** JAMS Pre processing failed
***
**** ERRORS/WARNINGS IN VARIABLE objin1
     1 error(s): BILEVEL: follower obj has no entry in follower equations
 
Could you tell me how to solve it? 






%"
>> bilevel q
>> min objin1 x("p1") y("p1",S) defin1 constraint1(S)
>> min objin2 x("p2") y("p2",S)  defin2 constraint2(S)
>> $offecho
>>
>> solve endorisk us emp min objout;
>
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yann buydens

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Feb 15, 2012, 6:07:13 AM2/15/12
to gamsworld
I just started over again with the problem in the emplibrary BARD721.
I think its because I used x("p1") etcetera. emp doesn't seem to like
that. I defined x1 instead of a vector x.

On 11 feb, 02:17, 胡辉 <hh24...@163.com> wrote:
> Hi,
> I tried to solve your model, problem is as below:
> EMP syntax error: key expected: is y (item 4 on line 2) but instance not in var
> iable rim
> --- EMP Summary (errors=2)
> Adjusted Constraint = 0
> Flipped Constraints = 0
> Dual Variable Maps = 0
> Dual Equation Maps = 0
> VI Functions = 0
> Equilibrium Agent = 0
> Bilevel Followers = 1
> Disjunctions = 0
> Logical Constraints = 0
> ***
> *** JAMS Pre processing failed
> ***
> **** ERRORS/WARNINGS IN VARIABLE objin1
> 1 error(s): BILEVEL: follower obj has no entry in follower equations
>
> Could you tell me how to solve it?
>
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