[Coin-discuss] license issues

Andreas Waechter andreasw at watson.ibm.com
Mon Sep 18 13:26:11 EDT 2006 

Hi,

Just a minor insignificant correction:  Ipopt was originally contributed 
by CMU, since it was written there.  However, since I then went to IBM, we 
decided to release it under a license that IBM would be happy with (and 
would allow me to keep working on it), and that was the CPL.

Andreas


On Mon, 18 Sep 2006, Brady Hunsaker wrote:

> I'll try to help clarify some of the confusion about COIN-OR's license 
> policy.  I'm a member of the Strategic Leadership Board, so I feel qualified 
> for that.  As to the legal questions of license specifics, I'll make a 
> personal statement at the end.
>
> COIN-OR allows project contributors to choose any software license that is 
> approved by the Open Source Initiative.  Dual-licensing is also allowed, and 
> we currently have one case of a dual-license (user's choice of CPL or GPL). 
> Both the CPL and GPL are approved as open-source licenses by the Open Source 
> Initiative.
>
> Most of the current code is licensed under the CPL, so we encourage new 
> project contributors to consider the CPL for compatibility.  This is not 
> required, however.  It is up to the project contributor.
>
> IPOPT was originally contributed by IBM.  IBM chose to use the CPL for all 
> the open-source code it has contributed to COIN-OR.  I don't know all the 
> reasons for this, but here are a few points:
> - IBM wrote the CPL to be exactly the way they want it.
> - The CPL has clauses relating to patents; the GPLv2 does not.
> - In my personal understanding, the CPL is closer to the LGPL, allowing use 
> as a library or separate module without the requirement that other code have 
> the same license.
>
> I hope that clears up some of the main COIN-OR questions.  If not, I'll be 
> happy to try again.
>
> ----
>
> As to the legal relationship of licenses, I can only speak for myself (not 
> for COIN-OR).  My understanding is similar to what Bill has written below. 
> IBM wanted to engage both research and industry communities when it 
> contributed IPOPT, and evidently believes that the CPL is the best way to do 
> that, despite the relative frequencies of licenses in other projects.  The 
> LGPL would be similar in some key ways, but I believe IBM probably evaluated 
> it and explicitly deciding against it.
>
> Unfortunately it's not possible to release binary code that combines code 
> under the CPL and GPL or LGPL.  It is possible to release source code that 
> interoperates, but the user would always be required to collect the two 
> different codes and compile them locally.  For example, some COIN-OR projects 
> allow the user to link to code under the GPL, such as gzip and bzip2 
> compression libraries.  This is not enabled by default, and we do not expect 
> to be able to distribute binaries with this feature because of license 
> incompatibilities.
>
> Brady
>
> Hart, William E wrote:
>> John:
>> 
>> I didn't help develop CPL, but my understanding is that the principal
>> motivation for CPL was that it enabled commercial entities to use the
>> code without enforcing code-distribution requirements on them.  Thus,
>> someone like IBM could integrate CPL code, modify it, and distribute it
>> commercially without being required to redistribute those changes to the
>> public.
>> 
>> This sort of policy goes against the grain of the GNU open source
>> distribution policy, but in practice I have observed that commercial
>> entities using CPL code remain interested in fostering improvements in
>> the code.
>> 
>> It's clear to me that this sort of license is not what you're interested
>> in for ASCEND.  I don't think you could argue that IPOPT _should_ be
>> distributed with the LGPL license.  However, the IPOPT developers are
>> free to license IPOPT under LGPL as well, for inclusion in a project
>> like ASCEND.
>> 
>> --Bill
>> 
>>> -----Original Message-----
>>> From: coin-discuss-bounces at list.coin-or.org 
>>> [mailto:coin-discuss-bounces at list.coin-or.org] On Behalf Of John Pye
>>> Sent: Monday, September 18, 2006 9:09 AM
>>> To: Discussions about open source software for Operations Research
>>> Subject: Re: [Coin-discuss] license issues
>>> 
>>> Hi Bill,
>>> 
>>> I'm not all that clear on it myself. I found these comments on Wikipedia:
>>> http://en.wikipedia.org/wiki/Common_Public_License
>>> 
>>> CPL would be one of the less common open source licenses. Given that it's 
>>> said to be incompatible with the far-and-away most common open source 
>>> license, namely the GPL, I'm curious why it was that CPL was chosen for 
>>> COIN? I wonder if you could perhaps explain what the conditions were that 
>>> you wanted to enforce?
>>> 
>>> In the case of my project, ASCEND, for example, we wanted to make a 
>>> completely free modelling tool that could not be swallowed up inside a 
>>> larger commercial piece of software without our explicit agreement.
>>> Perhaps it is important that use of IPOPT and other COIN software be 
>>> allowed inside commercial stuff. In that case, perhaps the LGPL would be a 
>>> better choice than the CPL?
>>> 
>>> Cheers
>>> JP
>>> 
>>> Hart, William E wrote:
>>> 
>>>> FYI, the discussion that JP refers to is available at:
>>>> 
>>>>  http://www.gnu.org/licenses/license-list.html
>>>> 
>>>> I can't say that I understand the gist of the incompatibility...
>>>> 
>>>> --Bill
>>>> 
>>>> 
>>>>> -----Original Message-----
>>>>> From: coin-discuss-bounces at list.coin-or.org
>>>>> [mailto:coin-discuss-bounces at list.coin-or.org] On Behalf Of John Pye
>>>>> Sent: Monday, September 18, 2006 7:59 AM
>>>>> To: coin-discuss at list.coin-or.org
>>>>> Subject: [Coin-discuss] license issues
>>>>> 
>>>>> Hi all,
>>>>> 
>>>>> I've just come across COIN and the IPOPT solver, and was thinking about 
>>>>> looking at it as a possible open source alternative to the CONOPT solver 
>>>>> that we currently rely on for some of the 
>>> functionality 
>>>>> in the ASCEND modelling environment (another CMU project).
>>>>> 
>>>>> I was wondering why IPOPT has chosen the Common Public License.
>>>>> According to the GNU website, this license is not 
>>> compatible with the 
>>>>> GPL, which means that although IPOPT is open source, we 
>>> can't legally 
>>>>> distribute it with our software. Perversely, it seems that it is easier 
>>>>> to use IPOPT in commercial projects than in free projects!
>>>>> 
>>>>> Is there a good reason why the CPL is applied to IPOPT -- perhaps 
>>>>> another license could be used instead, such as the GPL or LGPL license?
>>>>> 
>>>>> I note that this discussion also appears to have taken place on the 
>>>>> CppAd list, and the Boost license was suggested there as an alternative.
>>>>> 
>>>>> Cheers
>>>>> JP
>>>>> _______________________________________________
>>>>> Coin-discuss mailing list
>>>>> Coin-discuss at list.coin-or.org
>>>>> http://list.coin-or.org/mailman/listinfo/coin-discuss
>>>>> 
>>>>> 
>>>>> 
>>>> 
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>>> 
>> 
>> 
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>
> -- 
> Brady Hunsaker
> Assistant Professor
> Industrial Engineering
> University of Pittsburgh
> http://www.engr.pitt.edu/hunsaker/
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