Search found 8 matches

by Alexanre.ito
1 week ago
Forum: Syntax
Topic: commercial diameter - declare
Replies: 1
Views: 120

Re: commercial diameter - declare

I founded the answer:
Special Features for Mathematical Programs:
https://www.gams.com/latest/docs/UG_Lan ... tures.html
by Alexanre.ito
3 weeks ago
Forum: Syntax
Topic: problem with syntax of the equation
Replies: 12
Views: 458

Re: problem with syntax of the equation

I'd like to know if GAMS undestand this situation ... n nodes / n1 * n48 / a(n,n) /..../; .... alias(n,np,i,j); ... q(n) - scalar q(a) - variable ... eq1(a(i,j)).. q(a(n,np)) =e= sum(q(a(n,np)$(np=i)) + q(n) GAMS understand : eq(i) eq(i,j) but GAMS undestand: eq(a(i,j)) ??? my objective is to elabo...
by Alexanre.ito
3 weeks ago
Forum: Syntax
Topic: problem with syntax of the equation
Replies: 12
Views: 458

Re: problem with syntax of the equation

Renger wrote:
3 weeks ago
Hi

It is not clear what you want to do with this equation. My advice: write it down as a proper mathematical expression, read how to use the sum in GAMS as well as the $-sign, and proceed from there.

Cheers

Renger
GAMS understand :
eq(i)..
eq(i,j)..


but GAMS undestand:
eq(a(i,j)).. ???
by Alexanre.ito
3 weeks ago
Forum: Syntax
Topic: problem with syntax of the equation
Replies: 12
Views: 458

Re: problem with syntax of the equation

I'd like to know if GAMS undestand this situation ... n nodes / n1 * n48 / a(n,n) /..../; .... alias(n,np,i,j); ... q(n) - scalar q(a) - variable ... eq1(a(i,j)).. q(a(n,np)) =e= sum(q(a(n,np)$(np=i)) + q(n) GAMS undestand eq(i) and eq(i,j) but GAMS undestand eq(a(i,j)) ??
by Alexanre.ito
3 weeks ago
Forum: Syntax
Topic: problem with syntax of the equation
Replies: 12
Views: 458

Re: problem with syntax of the equation

I'd like to know if GAMS undestand this situation ... n nodes / n1 * n48 / a(n,n) /..../; .... alias(n,np,i,j); ... q(n) - scalar q(a) - variable ... eq1(a(i,j)).. q(a(n,np)) =e= sum(q(a(n,np)$(np=i)) + q(n) GAMS understand : eq(i) eq(i,j) but GAMS undestand: eq(a(i,j)) ??? my objective is to elabor...
by Alexanre.ito
1 month ago
Forum: Syntax
Topic: commercial diameter - declare
Replies: 1
Views: 120

commercial diameter - declare

Hi, I have a problem where I have to calculate the diameter of a pipe, using the equations I will find the diameter value that is a decimal number. But the diameter I will use is the commercial value, always selecting the next commercial size of the value found by the equations. Then I must analyze ...
by Alexanre.ito
1 month ago
Forum: Syntax
Topic: problem with syntax of the equation
Replies: 12
Views: 458

Re: problem with syntax of the equation

Renger wrote:
1 month ago
Looks fine, and as long as you have at least as many equations as variables in your model, there is nothing wrong with using an implicit definition of this variable.
Cheers
Renger
Thanks a lot.
by Alexanre.ito
1 month ago
Forum: Syntax
Topic: problem with syntax of the equation
Replies: 12
Views: 458

problem with syntax of the equation

I'm new with optimization and GAMS. I not sure how to declare the Manning equation. This equation describe the flow dynamic on free flow condition, considering geometry and viscosity. I declared scalar and variables as: man manning coef / 1.30e-2 / q(n,n) flow (m**3 per s) ir(n,n) inclination (m per...