how can i write equation at the pic?
gams dosent allow this "d(i,s).. 2*x(i,s,2)+x(i,s+1,1)+ x(i,s+1,2) =l= 2;"
help about an equation
Re: help about an equation
Hi,
Looks as if you want to refer to a particular set element explicitly in the third index position of x. In that case, set elements (aka labels) must be quoted.
Helping you would become a lot easier if you share your code such that users can reproduce the exact issue. Just saying GAMS doesn't allow some equation syntax may lack important context.
Fred
Looks as if you want to refer to a particular set element explicitly in the third index position of x. In that case, set elements (aka labels) must be quoted.
Helping you would become a lot easier if you share your code such that users can reproduce the exact issue. Just saying GAMS doesn't allow some equation syntax may lack important context.
Fred
Re: help about an equation
thanks a lot. i am just a beginner about GAMS. so i will be very thanksfull about any help
here is the my model
set
i hemsire numarası /1*20/
j gün numarası /1*30/
s /1*29/
k vardiya numarası /1*2/
w hafta sonu /1,2,8,9,15,16,22,23,29,30/
v hafta içi /3,4,5,6,7,10,11,12,13,14,17,18,19,20,21,24,25,26,27,28/
;
variables
x
z amaç fonk;
binary variables
x
;
equations
cost
a(j,k) her gündüz-gece vardiyasında en az 4 hemşire bulunsun
b(i,k) her hemşire ayda en az 4 hafta içi gündüz-gece vardiyasında çalışsın
c(i,k) her hemşire ayda en az 2 hafta sonu gündüz-gece vardiyasında çalışsın
d(i,s)
;
cost .. z =e= sum((i,j,k), x(i, j, k)) ;
a(j,k) .. sum((i), x(i,j,k)) =g= 4;
b(i,k).. sum((v), x(i,v,k)) =g= 4;
c(i,k).. sum((w), x(i,w,k)) =g= 2;
d(i,s).. 2*x(i,s,2)+x(i,s+1,1)+ x(i,s+1,2) =l= 2;
model ornek1/all/;
solve ornek1 using MIP minizing z;
display x.l, z.l;
here is the my model
set
i hemsire numarası /1*20/
j gün numarası /1*30/
s /1*29/
k vardiya numarası /1*2/
w hafta sonu /1,2,8,9,15,16,22,23,29,30/
v hafta içi /3,4,5,6,7,10,11,12,13,14,17,18,19,20,21,24,25,26,27,28/
;
variables
x
z amaç fonk;
binary variables
x
;
equations
cost
a(j,k) her gündüz-gece vardiyasında en az 4 hemşire bulunsun
b(i,k) her hemşire ayda en az 4 hafta içi gündüz-gece vardiyasında çalışsın
c(i,k) her hemşire ayda en az 2 hafta sonu gündüz-gece vardiyasında çalışsın
d(i,s)
;
cost .. z =e= sum((i,j,k), x(i, j, k)) ;
a(j,k) .. sum((i), x(i,j,k)) =g= 4;
b(i,k).. sum((v), x(i,v,k)) =g= 4;
c(i,k).. sum((w), x(i,w,k)) =g= 2;
d(i,s).. 2*x(i,s,2)+x(i,s+1,1)+ x(i,s+1,2) =l= 2;
model ornek1/all/;
solve ornek1 using MIP minizing z;
display x.l, z.l;
Re: help about an equation
Hi,
As indicated in my previous post and by the first error message
set elements must be quoted. After changing equation d to
the model solves.
I hope this helps!
Fred
As indicated in my previous post and by the first error message
Code: Select all
*** Error 145 in ...\new1.gms
Set identifier or quoted element expected
Code: Select all
d(i,s).. 2*x(i,s,'2')+x(i,s+1,'1')+ x(i,s+1,'2') =l= 2;
I hope this helps!
Fred
Re: help about an equation
thanks a lot it was what i need for solve it. have a good day
Re: help about an equation
i am so sorry but can i ask one more question
how can i assign x(1,3,2) to 1?
guess x('1','3','2')=1; dosent match what i want
how can i assign x(1,3,2) to 1?
guess x('1','3','2')=1; dosent match what i want
Re: help about an equation
Hi,
A variable has several attributes: https://www.gams.com/latest/docs/UG_Var ... Attributes
You need to specify which one you would like to use, e.g.
to set the variable's level to 1 or
to fix the variable at 1 (upper and lower bound set to 1).
A variable has several attributes: https://www.gams.com/latest/docs/UG_Var ... Attributes
You need to specify which one you would like to use, e.g.
Code: Select all
x.l('1','3','2')=1;
Code: Select all
x.fx('1','3','2')=1;
Re: help about an equation
thanks a lot again and again