[Coin-lpsolver] tableau column for artificials

[magh at lehigh.edu]

Hi John, 

Your unitTest does seem to pass. I am not quite sure why... below is the check
for col < numCols, that I hit if I try to get an artifical column using index =
numCols + i. 

void 
OsiClpSolverInterface::getBInvACol(int col, double* vec)
...
#ifndef NDEBUG
  int n = modelPtr_->numberColumns();
  if (col<0||col>=n) {
    indexError(col,"getBInvACol");
  }
#endif

Matt




> Matt,
> 
> I am confused by your notes.  getBInvACol(numberColumns+i,..) should get 
> the ith artificial and should not throw an exception.  The coding at line 
> 698 of Test/unitTest.cpp is an example.
> 
> Partly on this topic, I am in the middle of making changes to Clp so that 
> repeated calls are faster and so that the factorization is not deleted 
> etc.  These are designed to make the CBC->OSI->CLP combination faster but 
> may be useful in other contexts.  If anyone is brave enough to help me 
> test these changes over the next few months can they contact me and say 
> what they would want and whether they are using Clp via Osi or directly.
> 
> John Forrest
> 
> 
> 
> magh at lehigh.edu 
> Sent by: coin-lpsolver-bounces at list.coin-or.org
> 12/03/2004 04:34 PM
> 
> To
> coin-lpsolver at list.coin-or.org
> cc
> 
> Subject
> Re: [Coin-lpsolver] tableau column for artificials
> 
> 
> 
> 
> 
> 
> Sorry for posting to my own post (twice)... I often find myself having
> conversations with myself through email. It keeps me entertained. :)
> 
> Can't I just use getBInvCol(r, vec), where r is the row index of the 
> artificial
> variable?
> 
> Thanks,
> Matt
> 
> 
> > Sorry - I meant,
> > 
> > "column of the tableau for an artificial (non-basic) variable"
> > 
> > Thanks,
> > Matt
> > 
> > 
> > > Hi CLP,
> > > 
> > > In getBInvARow, you return a structural and artificial section from 
> the
> > > tableau.
> > > Is it possible to get a column of the tableau for an artificial 
> (basic)
> > > variable? 
> > > 
> > > Currently, getBInvACol throws an error if you ask for any column index 
> >
> > > numberColumns().
> > > 
> > > Thanks,
> > > Matt
> > > 
> > > 
> > > 
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