[Cbc] Very different results with CBC/CLP 2.7.7

[John Forrest]

Hervé

Your matrix does give Clp some problems.  I am not sure what changes to 
Clp (or Coin presolve) have affected runs.  With my latest trunk (not in 
svn) it solves with
-preoption 12 -primaltol 1.0e-5 -primals
but fails with latest stable.

stable works with
-presolve off -scaling off -primaltol 1.0e-5 -primals but takes 5-6 minutes.

Leaving aside the primal feasibility issues, it seems to be a scaling 
issue with objective.  I can give the unpresolved version a suboptimal 
basis and it declares it optimal.

I will carry on looking.

John Forrest