[Ipopt] Ipopt license

Wed May 5 14:24:29 EDT 2010

Hi Johan, 

Great question.  Here's a long answer. 

Q: The CPL was "superseded" by the EPL.  What happened? 
A:  This is the best explanation I know of --> 
http://dev.eclipse.org/blogs/mike/2009/04/16/one-small-step-towards-reducing-license-proliferation/ 
.   It also answers some helpful FAQ: 

4. I have a CPL-licensed project. What do I need to do?
You can continue to use it if you want to, although the whole reason we?re 
making this happen is because we wanted to provide projects with an easy 
option to migrate to the EPL to help reduce license proliferation.
There is a very simple path to moving your CPL-licensed project to the 
Eclipse Public License. Since the EPL has been denoted as the successor 
version of the CPL, you can use a provision in Section 7 (?In addition, 
after a new version of the Agreement is published, Contributor may elect 
to distribute the Program (including its Contributions) under the new 
version.?) to easily switch to the EPL.
5. When does this take effect?
Immediately. 
6. Wait a second! The CPL also says ?Each new version of the Agreement 
will be given a distinguishing version number.? How can the EPL 1.0 be a 
new version of the CPL 1.0?
Well, you?re right. We could have created a CPL 1.1 that simply pointed to 
the EPL 1.0. But frankly that seemed a lot more confusing than helpful. 
Especially since the licenses effectively differ by about one-and-a-half 
sentences. However, more importantly, the EPL is indeed the successor 
version to the CPL. The Eclipse Foundation and its members developed the 
EPL from the CPL by modifying those one-and-a-half sentences. The name of 
the license doesn?t change that history.

Q: What does this mean for IPOPT users? 
A: Becuase the CPL license was superseded by the EPL license (i.e., the 
contract changed), WITHOUT ANY CHANGES TO THE IPOPT CODE OR LICENSE FILES, 
anyone who could distribute IPOPT under the CPL can now distribute it 
under the EPL. 

Q: ...any plans to make the switch?
A: So to answer your original question, are there plans to switch?  Yes, 
we're talking about it.  Does it matter?  Not a lot.  Anyone who wants to 
redistribute the IPOPT code under the EPL already can. 

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------- Caution: More than You May Want to Know Section-----------
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Q: So why does it matter? 
A: Some lawyers believe that the person who takes the CPL code and 
distributes it under the EPL (aka "the Switcher") is liable under the CPL 
in the case of a lawsuit, but everyone who accepts the code from the 
Switcher under the EPL (aka "the Downstreamers") is only liable under the 
terms of the EPL. 

So, if you're happily using IPOPT under the current risk of lawsuit under 
the CPL - there's no issue.  You can be "the Switcher." 

But suppose not?  Suppose you are admantly opposed to the risk of using 
IPOPT under the CPL and will ONLY accept it under the EPL -- you won't be 
"the Switcher."  What do you do?  You have to find someone willing to be 
the Switcher - then you can get IPOPT under the EPL from them (if you 
believe like the lawyers, that you will only be liable under the EPL...but 
opinions vary on this...). 

This is my understanding as a non-lawyer.  If you're in this "caution" 
section and concerned about level of risk under the CPL vs EPL,  talk to 
your lawyer.   Hope this was helpul. 

Other potentially useful links:
CPL FAQs --> http://www.ibm.com/developerworks/library/os-cplfaq.html
EPL FAQs --> http://www.eclipse.org/legal/eplfaq.php

Robin

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Hi,

I have a question about the Ipopt license, CPL: According to OSI, CPL 
has been superseded by the Eclipse Public License (EPL) (
http://www.opensource.org/licenses/cpl1.0.php 
) - any plans to make the switch?

Best
/Johan

Johan Åkesson, PhD, Assistant Professor
Deptm. of Automatic Control              E-mail: 
johan.akesson at control.lth.se
Faculty of Engineering                           WWW: 
www.control.lth.se/user/jakesson
Lund University Phone:  +46 46 2228797
Box 118                  Fax:    +46 46 138118
221 00  LUND

----------------------------------------------------------------------------------
Robin Lougee, PhD
Program Manager, COIN-OR
IBM TJ Watson Research Center
1101 Kitchawan Road, Yorktown Heights, NY 10598
ph: 914-945-3032   fax: 914-945-3434 
robinlh at us.ibm.com
http://www.coin-or.org

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