<br><br><div class="gmail_quote">On Thu, Oct 25, 2012 at 8:55 PM, John Forrest <span dir="ltr"><<a href="mailto:john.forrest@fastercoin.com" target="_blank">john.forrest@fastercoin.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
Bo,<br>
<br>
Directly - very little of OSL. As in - read what OSL does and then do the same/different - a great deal.<br>
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The Coin-OR initiative was started at ISMP 2000 with me as "benevolent dictator" i.e. doing nothing. Osi solver interface came first and Cgl. However a need arose for a factorization (for Gomory cuts) and I had written a "child of OSL" code to do structured parallel simplex. I simplified the factorization from that (which explains some of the quirks).<br>
<br>
Having a factorization, it was natural to start on Clp. Basically the idea was to learn from the mistakes of OSL and make brand new mistakes.<br>
<br>
With Clp there had to be an OsiClp. The Osi interface specified a branch and bound function. So how hard can it be to write a Simple Branch and Bound code? I guessed 8 hours but it took 12. This became SBB but a) there was already some software called SBB and b) it stopped being simple - so Cbc.<br>
<br>
For medium sized problems Clp was slower than OSL had been so I lifted the OSL factorization code and made it into an alternative factorization CoinOslFactorization. So that is the only piece directly from OSL. OSL itself was an IBM product from a Research code YKTLP which was made into a product as a large oil company said they would buy an IBM mainframe plus Vector Feature rather than a cheaper lookalike mainframe IF YKTLP became a product. OSL was in Fortran (1987?) and later converted to C by a program f2c which does not produce elegant code (but then I have never been accused of writing elegant code).<br>
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I can hear the sound of snoring - but I hope that answers your question.</blockquote><div><br></div><div>Thanks you did, not snoring at all, I love such software stories.</div><div> </div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<span class="HOEnZb"><font color="#888888"><br>
<br>
John Forrest</font></span><div class="im HOEnZb"><br>
<br>
On 25/10/12 17:57, Bo Jensen wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
John,<br>
<br>
Just out of curiosity, what's the history of CLP/CBC/OSL, I mean how much of OSL were reused in some form ?<br>
<br>
/Bo<br>
<br>
</blockquote>
<br></div><div class="HOEnZb"><div class="h5">
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