dear dr
i have a question that i count find its answer for a long time.
please answer me if you know;
im working on MRCPCP(multi mode resource constrained project scheduling problem) and i want to code my problem with GAMS.
but i dont know how can i specify upper and lowe bound for summation over time. because this summation must be overt " t "and for every activity this " t " must be from “EF(j)” to “LF(j)”. i have problem to code it in GAMS. please help me if you know. thank you
AZAD AMIRI
best regards
Date: Sun, 14 Apr 2013 06:10:01 -0700
From: ati_h2005@yahoo.com
Subject: Re: scanning a set of values loop statement
To: gamsworld@googlegroups.com
hi,
note that, loop is working with ‘t’ not ‘i’
loop(t,
j = x(t);
display j;
);
From: “byungdo.chung@gmail.com”
To: gamsworld@googlegroups.com
Cc: Hajinezhad
Sent: Saturday, April 13, 2013 7:52 AM
Subject: Re: scanning a set of values loop statement
Hi, Thank you for your help.
I tried what you mentioned but there is an error atr “j = x(i);”
“149 Uncontrolled set entered as constant”
The following is what I tested.
sets i /1 * 3/
t(i) ;
parameter x(i), j;
x(‘1’) = 1;
x(‘2’) = 3;
x(‘3’) = 7;
t(i) = yes;
loop(t,
j = x(i);
display j;
);
Could you let me know the code you tested?
Thank you again.
On Saturday, April 13, 2013 3:05:33 AM UTC+9, Hajinezhad wrote:
Hi,
I run the example model without the line " solve z → (z is a function of j);"; there was no error. I think the problem is that you use the set “i” to define some equations, and also for loop. In this case, you can define a subset of “i”
set
t(i);
.
.
.
t(i) = yes;
loop(t,
j = x(i);
.
.
);
From: “byungd...@gmail.com”
To: gams...@googlegroups.com
Sent: Friday, April 12, 2013 7:41 PM
Subject: scanning a set of values loop statement
I’d like to assign values of a set of parameters, then use the value one by one using loop statement.
For example…
sets i /1 * 3/ ;
parameter x(i), j;
x(‘1’) = 1;
x(‘1’) = 3;
x(‘1’) = 7;
loop(i,
j = x(i);
solve z → (z is a function of j);
);
In GAMS, " j = x(i);" causes an error. Is there any way to solve the problem?
Thank you for your help in advance.
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