Hi,

I am learning to work using GAMS and I have licensed software comprising of base and path solvers.

In the process of learning, I formulated a small program and trying to simulate that if co(i,j) increase by 1.25 times, what is the value of total?

When I run this program, I got the changed value of c(i,j) but no change in value of total. I want to identify the mistake but not able to; please guide.

$title Exercise of sum

Set i /punjab, haryana, UP, Rajasthan/

j /wheat, barley, maize/;

Table co(i,j) quantity transported

wheat barley maize

punjab 25 15 10

haryana 20 25 15

UP 30 24 22

Rajasthan 24 23 18;

Parameter

totalo;

Totalo = sum((i,j),co(i,j));

Variables

total

c(i,j);

Equation

Equa;

Equa.. total =e= sum((i,j),c(i,j));

total.L = totalo;

c.L(i,j) = co(i,j);

*simmulate

Parameter

c1(i,j);

c1(i,j) = co(i,j)*1.25;

c.l(i,j) = c1(i,j);

co(i,j) = c1(i,j);

Display total.l, c.l;

## Simulation

### Re: Simulation

In order to exercise/execute an equation (to calculate

-Michael

*total*) you need to solve a model with a*solve*statement. So an equation is**not**like an F9 button, i.e as soon as you change the values it recalculated other values. You need to trigger this action by a solve of a model. I suggest you study the tutorial (https://www.gams.com/latest/docs/UG_Tutorial.html) and other introductory chapters of the GAMS documentation and even perhaps take an (on-line) class.-Michael

### Re: Simulation

Thanks a lot. Also guide me when and where I can take on line classes.