[Coin-discuss] CBC applied to maximization problems

[Michael Hennebry]

On Tue, 2 Dec 2008, Hart, William E wrote:

> But how does the wrapper know when to flip, if it's simply being handed an LP file?  Do I need to parse the LP file before CBC does?

That is what I had in mind.
Presumably it wouldn't take a lot of parsing,
especially if you were willing to settle for a warning.
Also, min or max could be a required parameter of the script.

Since CBC will give you a warning now, it doesn't matter much.

>> On Tue, 2 Dec 2008, Hart, William E wrote:
>>
>>> Here's my scenario.  I have a wrapper script that passes a
>> LP or MPS file to CBC, and then parses the output.  The
>> results of this optimization process are then returned to the
>> user.  The confusing thing is that a user sees minimization
>> results when passed a maximization problem.  Logically, it's
>> identical, but this will be surprising and confusing to
>> non-technical users.

[Michael Hennebry:]
>> I think that the answer is to have the wrapper do the flipping.
>> The wrapper can print the warning.
>> The wrapper could also negate any output that needed negating.

-- 
Michael   hennebry at web.cs.ndsu.NoDak.edu
"Pessimist: The glass is half empty.
Optimist:   The glass is half full.
Engineer:   The glass is twice as big as it needs to be."