[Coin-discuss] Controlling the level of output from solvers

[Lou Hafer]

Michal,

	Some specific suggestions, then some general comments.
	
	First, what version of OSI are you using?  In the most recent release,
and the current stable version head, OsiGlpk does implement setHintParam, and
resolve does not force LPX_K_MSGLEV to 1.

	OsiGlpk in Osi/trunk chooses lpx_intopt when available, and tries to do
the right thing to use glpk's built-in preprocessing and cutting planes. Don't
know if it's practical for you to use the trunk.

	In general, setHintParam(OsiDoReducePrint,true,OsiHintDo) should turn
off output.  You could try OsiForceDo, but be prepared to catch a throw if the
solver doesn't support the hint.

	We're working towards uniform behaviour for the various OSI solvers, and
we're making good progress.  But OSI is a collective effort, and we're really
dependent on the maintainers and users of individual OsiXXX interfaces.  No
individual maintainer is an expert in all the underlying solvers.  Output
control is one of those things that varies wildly from one solver to the next.
Contributions welcomed --- the best thing to do is file a ticket against the
particular OsiXXX interface.  (Go to https://projects.coin-or.org/Osi/wiki, log
in, and you'll see a `new ticket' option in the navigation bar at the top of the
page).  Tell us what calls need to be made to the underlying solver to suppress
output, or acheive a particular level of output.

							Lou