Solver BARON Cannot Execute Log function

GAMS
1

Hi All,
I have a MINLP problem for which we recently purchased BARON license to solve.
Unfortunately, whenever I try to use BARON as the solver, it reports capability problem and then halts.

So, does this mean that BARON cannot solve logarithmic functions?
Other solvers seem to work but would be great to see how BARON performs also. Anybody has similar experience or am I doing something wrong?

–
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2

Crystal,

Why not just try a simple model to see for yourself if BARON can
handle log functions? I tried a little model (below) and BARON
handles it just fine.

In general, we try to write some messages in the log and/or listing
file to give some detail about the capability error. For example,
BARON will reject models with trig functions. Have a good look at the
log or listing files or try debugging the model by removing equations
until you find that BARON accepts the model.

-Steve

variables x, y, z;
x.lo = 1; x.up = 4;
y.lo = 4; y.up = 4;

equations o;

o… z =e= power(x,3) - sqr(2y) + log(x) + log(10y+2);

model m / o /;
solve m using nlp min z;


On Tue, Sep 18, 2012 at 5:28 AM, Crystal wrote:

Hi All,
I have a MINLP problem for which we recently purchased BARON license to
solve.
Unfortunately, whenever I try to use BARON as the solver, it reports
capability problem and then halts.

So, does this mean that BARON cannot solve logarithmic functions?
Other solvers seem to work but would be great to see how BARON performs
also. Anybody has similar experience or am I doing something wrong?

–
“gamsworld” group.
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https://groups.google.com/d/msg/gamsworld/-/iS2WZNcDT7EJ.
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3

Alright Steve,

Thank you for the response.
One other quick question. I know BARON can use CONOPT, IPOPT, MINOS and SNOPT as NLP solvers. However, I know IPOPT is packaged with licensed GAMS and my license BARON should be able to use it.

What I don’t understand is this: I have licensed GAMS/BARON but as my solver list shows, IPOPT is listed as DEMO. So, do I need another license to run Full version of IPOPT?

Thanks.




On Tuesday, September 18, 2012 6:28:30 PM UTC+9, Crystal wrote:

Hi All,
I have a MINLP problem for which we recently purchased BARON license to solve.
Unfortunately, whenever I try to use BARON as the solver, it reports capability problem and then halts.

So, does this mean that BARON cannot solve logarithmic functions?
Other solvers seem to work but would be great to see how BARON performs also. Anybody has similar experience or am I doing something wrong?

–
To view this discussion on the web visit https://groups.google.com/d/msg/gamsworld/-/POLALnsYzssJ.
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