Hi,
In the “A GAMS Tutorial by Richard E. Rosenthal” (https://www.gams.com/latest/docs/UG_Tutorial.html), I’m trying to run the model several times in a sequential way in order to see the influence of changing same SCALAR/PARAMETERS in each model run
Problem 1
What I want to do is to run the model several times with diferent “f” (Scalar f freight in dollars per case per thousand miles /90/) to see the impact (sensibility) on the model results when I change “f” from 90 to other value (30, 40 50, … , 130, 140, 150).
Problem 2
Very similar to the first one. The only difference is that I want to try the Seattle capacity (350 cases) to 250,300,400 and 450 and see the impact on the optimization results
Bottom line, I want (if possible) to run the model several times with some differences in the SCALAR and/or in the PARAMETERS
Does anyone knows how to do this? (if possible)
Thanks
Paulo
$title a transportation model
Sets
i canning plants / seattle, san-diego /
j markets / new-york, chicago, topeka / ;
Parameters
a(i) capacity of plant i in cases
/ seattle 350
san-diego 600 /
b(j) demand at market j in cases
/ new-york 325
chicago 300
topeka 275 / ;
Table d(i,j) distance in thousands of miles
new-york chicago topeka
seattle 2.5 1.7 1.8
san-diego 2.5 1.8 1.4 ;
Scalar f freight in dollars per case per thousand miles /90/ ;
Parameter c(i,j) transport cost in thousands of dollars per case ;
c(i,j) = f * d(i,j) / 1000 ;
Variables
x(i,j) shipment quantities in cases
z total transportation costs in thousands of dollars ;
Positive Variable x ;
Equations
cost define objective function
supply(i) observe supply limit at plant i
demand(j) satisfy demand at market j ;
cost … z =e= sum((i,j), c(i,j)*x(i,j)) ;
supply(i) … sum(j, x(i,j)) =l= a(i) ;
demand(j) … sum(i, x(i,j)) =g= b(j) ;
Model transport /all/ ;
Solve transport using lp minimizing z ;
Display x.l, x.m;