<br><font size=2 face="sans-serif">Paulo,</font>
<br>
<br><font size=2 face="sans-serif">I don't see why the time should have
increased compared to setObjectiveAndRefresh as I was just doing part of
that code.</font>
<br>
<br><font size=2 face="sans-serif">However I was being stupid. I
had put in the dual update but in an odd place in the sequence of the code
AND with a bug. So I have taken out the extra parameter I put in
yesterday and it should be faster.</font>
<br>
<br><font size=2 face="sans-serif">John Forrest</font>
<br>
<br>
<br>
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<td width=40%><font size=1 face="sans-serif"><b>"Paulo J. S. Silva"
<pjssilva@ime.usp.br></b> </font>
<br><font size=1 face="sans-serif">Sent by: coin-lpsolver-bounces@list.coin-or.org</font>
<p><font size=1 face="sans-serif">06/08/2006 03:45 PM</font>
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<div align=right><font size=1 face="sans-serif">To</font></div>
<td><font size=1 face="sans-serif">coin-lpsolver@list.coin-or.org</font>
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<td>
<div align=right><font size=1 face="sans-serif">cc</font></div>
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<div align=right><font size=1 face="sans-serif">Subject</font></div>
<td><font size=1 face="sans-serif">Re: [Coin-lpsolver] Shouldn't primalPivotResult
update reduced costs?</font></table>
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<br><tt><font size=2><br>
> primalPivotResult is just the last part of a primal iteration in Clp<br>
> (as no other solver implements it). Normally the reduced costs
are<br>
> updated at the beginning of the next iteration. However I agree
that<br>
> if you are using primalPivotResult you would expect the reduced costs<br>
> to be updated. I have added an extra parameter to primalPivotResult<br>
> to update dual solution which defaults to false so that nobody will
be<br>
> affected. Tell me if it does not do what you want? <br>
<br>
It is working now, thanks. However, the time for a primalPivotResult<br>
increased a lot (it was multiplied by 2). I'll e-mail you personally on<br>
this subject as the discussion may not be relevant for everybody.<br>
<br>
> I have always been a little uneasy about the "build your own
simplex"<br>
> parts of OsiSolverInterface and assuming that only Clp will ever<br>
> implement it, it may be better to approach it in a different way.
If<br>
> I knew how people use this interface I could add a virtual class to<br>
> Clp - rather like ClpEventHandler which would modify the behavior
of<br>
> Clp without continually entering and leaving it. This would
be more<br>
> robust and faster. <br>
<br>
IMHO, if only Clp is going to implement this part of the interface, you<br>
are probably be right. I wrote my code using Osi, instead of using pure<br>
Clp, with the hope to test some day the "same" code with other
solver. <br>
I'll take a closer look at ClpEventHandler and pure Clp. I was only<br>
using it through OsiInterface until now.<br>
<br>
Best,<br>
<br>
Paulo<br>
<br>
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