[Coin-lpsolver] Sbb: Use of setTestForDuplicateIndex and CoinMessages

[Jean-Sebastien Roy]

John J Forrest wrote:

> The reason ClpMessage was being called so much was that in 
> OsiClpSolverInterface::resolve a "lightweight" copy of fixed model is 
> made as it seemed safer as then hints could be used on this created 
> model.  Unhappily this lightweight copy did have message creation and 
> this can be an overhead on very small models.  As far as I can see it 
> does no harm to use the fixed model.  This does improve times on small 
> models significantly.  If anyone does notice any adverse effects 
> please tell me.
>
> For setTestForDuplicateIndex I have effectively removed it when called 
> from fullset.  This is perfectly safe as there is no way a dense 
> vector can have duplicates!  However I only see a small improvement. 
>  Can you tell me if my changes help more for you?

I re-ran a set of test, and the results varies quite a lot between 
platforms (Linux/FreeBSD or Solaris).
On FreeBSD, during the profiling, the difference is considerable: With 
the test for duplicate index, CoinPackedVector::CoinPackedVector(int, 
double const *, bool) takes 31.9 % of the total time (1902 seconds). 
Without, it takes 0.3 %, of 1198 seconds.
But the profilng results seems quite unreliable since once the profiling 
is removed, the difference between runs is only 10% (a bit more on Solaris).

I updated the source incorporating your changes and ran Sbb on a small 
problem :
Before : 40s
After : 21s

That's really nice. Many thanks !

js