Add loglevel control to Osi about osi HOT 2 OPEN

Comment by @LouHafer created at 2008-01-08 22:52:00

Essentially unchanged as 0.97 moves to 0.98.

You can use messageHandler()->setLogLevel() to adjust the log level of the OSI handler, and the OsiDoReducePrintLevel hint to (try to) affect the print level of the solver. But this is admittedly clumsy. Most annoying, there's no way to get at the message handler for a CoinMpsIO
object, which by default is annoyingly chatty.

There's a lot to be said for virtual methods here, because Leo's right --- each underlying solver has its own i/o control.

from osi.

passInMessageHandler() is virtual in current Osi code and a number of OsiXyz implementations use it to setup the solvers message handling. Regarding setLogLevel(), many OsiXyz implementations check the loglevel in the message handler when it comes to a solve and set the solvers loglevel parameter accordingly.

from osi.