[Coin-lpsolver] Best way to bring an instance into CLP?

[Lasse Kliemann]

* Message by -Lasse Kliemann- from Fri 2008-01-18:
> There are so many ways to bring an LP into the CLP solver.
> 
> I figured out at least the following:
> 
> 
> 1) CoinPackedMatrix --> ClpModel (via loadProblem)
> 
> 2) CoinModel --> ClpModel (via loadProblem)
> 
> 3) CoinBuild --> CoinModel (via addColumns or addRows) 
>              --> ClpModel (via loadProblem)
> 
> 4) CoinBuild --> ClpModel (via addColumns or addRows) 
> 
> 5) CoinPackedMatrix --> OsiClpSolverInterface (via loadProblem)
> 
> 6) CoinModel --> OsiClpSolverInterface (via loadFromCoinModel)
> 
> 7) CoinBuild --> CoinModel (via addColumns or addRows) 
>              --> OsiClpSolverInterface (via loadFromCoinModel)
 
Oh, there are even more:

9) CoinBuild --> OsiClpSolverInterface (via addRows or addCols)

And we can also load rows or columns given by vectors of indices and elements 
(what I assumed to be the starting point all the time) directly into ClpModel 
or OsiClpSolverInterface via addRow or addCol.
 

> Which of these is the best in terms of memory usage?
> Which is the best in terms of runtime efficiency?
> 
> As far as I understood, CoinBuild helps to boost runtime efficiency. Hence, 
> number 3 or number 7 could be the fastest solution. However, memory usage is 
> an issue in my application.
> 
> So far, I've been using alternative number 6, which I found pretty fast 
> already (even without the use of CoinBuild). The program aborts with 'out of 
> memory' on instances of a certain size. These instances can be solved, 
> however, when loaded directly into GLPK; I have not tried loading them 
> directly into CLP yet. Before I try all possible ways to find out the best, 
> maybe someone can give me a hint.
> 
> Thanks a lot for your advice!
> 
> Lasse
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