sum of weight equal to 1

GAMS
1

Hello,

I have three weights let’s say: w1=U[0,1], w2=U[0,1], w3=U[0,1].

I want to solve a model only if the sum of the three weights are equal to 1 or w1+w2+w3=1.

I did the following:

set i/1*100/;
.
.
.
w1(i)=uniform(0,1);
w2(i)=uniform(0,1);
w3(i)=uniform(0,1);
.
.
.
alias(i,ii);
loop(ii,
if( w1(i)+w2(i)+w3(i)=1,
Solve MODEL MAX OBJ;
);
);


But after the first iteration it stops.

Can you please help me?

Konstantinos Petridis

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2

Hi,

You need to put w1, w2 and w3 inside the loop. In your current code these values are updating just once. See the below code:

set i/1*100/;
.
.
.
.
.
.
alias(i,ii);
loop(ii,
w1(i)=uniform(0,1);
w2(i)=uniform(0,1);
w3(i)=uniform(0,1);
if( w1(i)+w2(i)+w3(i)=1,
Solve MODEL MAX OBJ;
);
);

Thanks.
Maruf
ISE, MSU


On Fri, Oct 4, 2013 at 9:16 AM, Κωνσταντίνος Πετρίδης wrote:

Hello,

I have three weights let’s say: w1=U[0,1], w2=U[0,1], w3=U[0,1].

I want to solve a model only if the sum of the three weights are equal to 1 or w1+w2+w3=1.

I did the following:

set i/1*100/;
.
.
.
w1(i)=uniform(0,1);
w2(i)=uniform(0,1);
w3(i)=uniform(0,1);
.
.
.
alias(i,ii);
loop(ii,
if( w1(i)+w2(i)+w3(i)=1,
Solve MODEL MAX OBJ;
);
);


But after the first iteration it stops.

Can you please help me?

Konstantinos Petridis

–
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\

Mohammad Marufuzzaman
Industrial & Systems Engineering
Mississippi State University, USA
E-mail: maruf237@gmail.com

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3

Hi Konstantinos
You should use i not ii in the loop.
Cheers
Renger

sent from my iPad

Am 04.10.2013 um 16:18 schrieb “Κωνσταντίνος Πετρίδης” :

Hello,

I have three weights let’s say: w1=U[0,1], w2=U[0,1], w3=U[0,1].

I want to solve a model only if the sum of the three weights are equal to 1 or w1+w2+w3=1.

I did the following:

set i/1*100/;
.
.
.
w1(i)=uniform(0,1);
w2(i)=uniform(0,1);
w3(i)=uniform(0,1);
.
.
.
alias(i,ii);
loop(ii,
if( w1(i)+w2(i)+w3(i)=1,
Solve MODEL MAX OBJ;
);
);

But after the first iteration it stops.

Can you please help me?

Konstantinos Petridis

–
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4

Hi Konstantinos



What is the probability that the sum of three random numbers is 1? My guess is zero. This means that you will not solve any model instance, at least not with this probability distribution.



Regards



Arne


\

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 Renger van Nieuwkoop
Sent: Friday, October 04, 2013 5:11 PM
To:
Subject: Re: sum of weight equal to 1



Hi Konstantinos

You should use i not ii in the loop.

Cheers

Renger


sent from my iPad


Am 04.10.2013 um 16:18 schrieb “Κωνσταντίνος Πετρίδης” :

Hello,

I have three weights let’s say: w1=U[0,1], w2=U[0,1], w3=U[0,1].

I want to solve a model only if the sum of the three weights are equal to 1 or w1+w2+w3=1.

I did the following:

set i/1*100/;
.
.
.
w1(i)=uniform(0,1);
w2(i)=uniform(0,1);
w3(i)=uniform(0,1);
.
.
.
alias(i,ii);
loop(ii,
if( w1(i)+w2(i)+w3(i)=1,
Solve MODEL MAX OBJ;
);
);


But after the first iteration it stops.

Can you please help me?

Konstantinos Petridis

–
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5

I would like to thank you all for your responses…

They were very helpful.

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