GAMS World Forum

I founded the answer:
Special Features for Mathematical Programs:
https://www.gams.com/latest/docs/UG_Lan ... tures.html

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...

Renger wrote: ↑4 years 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)).. ???

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)) ??

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...

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 ...

Renger wrote: ↑4 years 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.

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...