[Coin-discuss] Warmstart/basis reuse

[Esben Mose Hansen]

On Thursday July 19 2007 15:48:45 John J Forrest wrote:
> Esben,
>
> Yes that is what basisin and out do.  They correspond to INSERT and PUNCH
> in IBM's MPSX/370 code - you can tell how long ago that is from "punch".
> XL meant remove second variable from basis, set it to lower bound and
> replace by first variable.  XU to upper bound.  There are also UL, LL and
> BS.
>
> Saving and restoring warmstart and solution should give same result.

And it does. I even read through the readMps and writeMps functions to make 
sure that this is equivalent. Sounds easier than it were, too ;)

I did wonder about the solution contra the columnactivity. What is a 
columnactivity? (Or is there an article or something I can read to understand 
this)?

Anyway, for people that want to do warmstart, this is the way: Set the basis 
with "CoinSolveClpInterface::setWarmStart()" using the output from 
getWamtStart(), and set the solution 
with "CoinSolveClpInterface::setColSolution() from getColSolution(). "

Thanks again for your help!

-- 
regards, Esben