SMIN FUNCTION IS NOT WORKING

GAMS
1

Hello GAMSworld,

I observed a dysfunction with SMIN function.

I run the following model:

solve model1 max obj using lp

data(‘xx1’)=x1.l;
data(‘xx2’)=x2.l;
data(‘xx3’)=x3.l;
data(‘xx4’)=x4.l;

solve model2 max obj1 using lp/dnlp

I set two additional constraints in model 2 which are the following:

CONMAX… XMAX=E=SMAX(i, data(i)); /data(i) parameter, set i/xx1*xx4/, XMAX, XMIN nonnegative variables.
CONMIN… XMIN=E=SMIN(i, data(i));

After getting the results data(xx1)=0.661, data(xx2)=0.339 and XMAX=0.661 but XMIN=0… which consequently means that SMIN function is not working properly.

Can please anyone help?

thank you in advance,

Konstantinos Petridis

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2

Konstantinos Petridis:



You mention two elements in your ‘data’ parameter, but there are four elements in your set. I expect that the last two data values are zero (which are not printed by Display) and SMIN is therefore doing exactly what it should.



Regards



Arne Stolbjerg Drud


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Arne Stolbjerg Drud

ARKI Consulting & Development A/S

Bagsvaerdvej 246A, DK-2880 Bagsvaerd, Denmark

Phone: (+45) 44 49 03 23, Fax: (+45) 44 49 03 33, email: adrud@arki.dk



From: gamsworld@googlegroups.com [mailto:gamsworld@googlegroups.com] On Behalf Of ???sta?t??? ?et??d??
Sent: Friday, September 13, 2013 8:26 AM
To: gamsworld@googlegroups.com
Subject: SMIN FUNCTION IS NOT WORKING



Hello GAMSworld,

I observed a dysfunction with SMIN function.

I run the following model:

solve model1 max obj using lp

data(‘xx1’)=x1.l;
data(‘xx2’)=x2.l;
data(‘xx3’)=x3.l;
data(‘xx4’)=x4.l;

solve model2 max obj1 using lp/dnlp

I set two additional constraints in model 2 which are the following:

CONMAX… XMAX=E=SMAX(i, data(i)); /data(i) parameter, set i/xx1*xx4/, XMAX, XMIN nonnegative variables.
CONMIN… XMIN=E=SMIN(i, data(i));

After getting the results data(xx1)=0.661, data(xx2)=0.339 and XMAX=0.661 but XMIN=0… which consequently means that SMIN function is not working properly.

Can please anyone help?

thank you in advance,

Konstantinos Petridis

–
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3

Hi Kostas,
Default value for partially assigned parameter data(i) is zero.
If you only specify :
data(‘xx1’) = 0.661 ;
data(‘xx2’) = 0.339 ;
then, implicitely, you will also have
data(‘xx3’) = 0 ;
data(‘xx4’) = 0 ;

… which tends to indicate that SMIN works properly.
By the way, if data is indeed a parameter, there is no need to obtain XMIN by the means of constraints and variables, you may estimate it as a simple paramter – no need to resort to DNLP for this.

Hope this helps

dax


Le vendredi 13 septembre 2013 08:25:50 UTC+2, Κωνσταντίνος Πετρίδης a écrit :

Hello GAMSworld,

I observed a dysfunction with SMIN function.

I run the following model:

solve model1 max obj using lp

data(‘xx1’)=x1.l;
data(‘xx2’)=x2.l;
data(‘xx3’)=x3.l;
data(‘xx4’)=x4.l;

solve model2 max obj1 using lp/dnlp

I set two additional constraints in model 2 which are the following:

CONMAX… XMAX=E=SMAX(i, data(i)); /data(i) parameter, set i/xx1*xx4/, XMAX, XMIN nonnegative variables.
CONMIN… XMIN=E=SMIN(i, data(i));

After getting the results data(xx1)=0.661, data(xx2)=0.339 and XMAX=0.661 but XMIN=0… which consequently means that SMIN function is not working properly.

Can please anyone help?

thank you in advance,

Konstantinos Petridis

\

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