Solver baron is a global nonlinear solver based on the BARON solver by
Nikolaos V. Sahinidis and co-authors. See
http://archimedes.cheme.cmu.edu/?q=baron
http://www.minlp.com/
For much more detail on BARON, including pointers to papers, see the
accompanying baron_manual.pdf.
It is most convenient to invoke baron with AMPL's solve command:
ampl: option solver baron;
ampl: solve;
but baron can also be run separately, with invocation syntax
baron stub [-AMPL] [keywd=[value] ...]
in which stub comes from AMPL's write command. For example,
> ampl -obfoo foo.mod foo.dat
> baron foo
demonstrates running baron separately; the ampl invocation writes file
foo.nl (stub = "foo"), which baron reads.
Command-line arguments to baron either have the form
keywd
or
keywd=value
where keywd is one of the keywords described below. Alternatively,
you can invoke baron the way AMPL's solve command does, i.e.,
baron stub -AMPL [keywd=value ...]
where stub was specified in
ampl -obstub ...
or
ampl -ogstub...
Such an invocation causes baron to read from stub.nl and to write stub.sol.
-----------------
Controlling baron
-----------------
Baron reads keywords and values from the environment (shell) variable
baron_options and from the command line. Execute
baron -?
or (if your shell requires ? to be quoted)
baron '-?'
for a summary of baron usage and
, baron -=
(or baron '-=') for a summary of keywords peculiar to the AMPL/BARON
driver "baron".
------------------
Sample Invocations
------------------
If you're using AMPL, just say
option solver baron;
solve;
If you've executed, say,
ampl -objunk junk.model junk.data
then you could say
baron junk epsr=1e-4 lsolver=minos
to force baron to use relative tolerance .0001 between the function
value at the solution returned and a lower bound thereon and to use
local solver minos. (This assumes a license for the AMPL/MINOS solver
"minos" is available.) With the Bourne shell, either of the invocations
baron_options='epsr=1e-4 lsolver=minos' baron junk
or
baron_options='epsr=1e-4 lsolver=minos'
export baron_options
baron junk
would have the same effect; within AMPL, specifying
option baron_options 'epsr=1e-4 lsolver=minos', solver baron;
solve;
would also have this effect.
-----------------------
solve_result_num values
=======================
Here is a table of solve_result_num values that "baron" can return to
an AMPL session, along with the text that appears in the associated
solve_message.
Value Message
0 optimal within tolerances
100 numerical difficulties but possibly optimal
150 feasible but insufficient progress
200 infeasible
201 infeasible, IIS found
202 infeasible, IS found, possibly not irreducible
203 infeasible, IIS sought but not found
Nikolaos V. Sahinidis and co-authors. See
http://archimedes.cheme.cmu.edu/?q=baron
http://www.minlp.com/
For much more detail on BARON, including pointers to papers, see the
accompanying baron_manual.pdf.
It is most convenient to invoke baron with AMPL's solve command:
ampl: option solver baron;
ampl: solve;
but baron can also be run separately, with invocation syntax
baron stub [-AMPL] [keywd=[value] ...]
in which stub comes from AMPL's write command. For example,
> ampl -obfoo foo.mod foo.dat
> baron foo
demonstrates running baron separately; the ampl invocation writes file
foo.nl (stub = "foo"), which baron reads.
Command-line arguments to baron either have the form
keywd
or
keywd=value
where keywd is one of the keywords described below. Alternatively,
you can invoke baron the way AMPL's solve command does, i.e.,
baron stub -AMPL [keywd=value ...]
where stub was specified in
ampl -obstub ...
or
ampl -ogstub...
Such an invocation causes baron to read from stub.nl and to write stub.sol.
-----------------
Controlling baron
-----------------
Baron reads keywords and values from the environment (shell) variable
baron_options and from the command line. Execute
baron -?
or (if your shell requires ? to be quoted)
baron '-?'
for a summary of baron usage and
, baron -=
(or baron '-=') for a summary of keywords peculiar to the AMPL/BARON
driver "baron".
------------------
Sample Invocations
------------------
If you're using AMPL, just say
option solver baron;
solve;
If you've executed, say,
ampl -objunk junk.model junk.data
then you could say
baron junk epsr=1e-4 lsolver=minos
to force baron to use relative tolerance .0001 between the function
value at the solution returned and a lower bound thereon and to use
local solver minos. (This assumes a license for the AMPL/MINOS solver
"minos" is available.) With the Bourne shell, either of the invocations
baron_options='epsr=1e-4 lsolver=minos' baron junk
or
baron_options='epsr=1e-4 lsolver=minos'
export baron_options
baron junk
would have the same effect; within AMPL, specifying
option baron_options 'epsr=1e-4 lsolver=minos', solver baron;
solve;
would also have this effect.
-----------------------
solve_result_num values
=======================
Here is a table of solve_result_num values that "baron" can return to
an AMPL session, along with the text that appears in the associated
solve_message.
Value Message
0 optimal within tolerances
100 numerical difficulties but possibly optimal
150 feasible but insufficient progress
200 infeasible
201 infeasible, IIS found
202 infeasible, IS found, possibly not irreducible
203 infeasible, IIS sought but not found
