Clearer documentation of license

[tkelman]

Hi, I realize much of the code here has been publicly available on Netlib for many years, but would it be possible to formally assign a license? Ideally an OSI-approved commonly recognized license, from a list such as http://spdx.org/licenses.

I ask because Linux distributions can be very picky about licenses of packages, and it would be most convenient for users to be able to install libraries such as ASL in binary form from their package manager. That also allows other projects such as Ipopt, or tools that call AMPL from other languages, a much simpler installation path including ASL functionality than the current method which requires manual download of the ASL source code from Netlib or this repository, and forcing every user to compile the source code themselves. Using an established license would make it possible to redistribute compiled binaries of the already open-source components of AMPL, which is a much better experience for users. Please consider it.

[tkelman]

Sorry, my mistake, I see now that essentially all of the files under src/asl/solvers have a license header that is "MIT Old Style with legal disclaimer." https://fedoraproject.org/wiki/Licensing:MIT?rd=Licensing/MIT#Old_Style_with_legal_disclaimer

Maybe just clearer documentation of the license status would be nice to have.

[vitaut]

You are right, ASL and AMPL/MP are distributed under the old-style MIT license with legal disclaimer. I've added a license document to clarify this: https://github.com/ampl/mp/blob/master/LICENSE.rst. The AMPLGSL library can also distributed under GPL for compatibility with GSL.

[tkelman]

Thank you very much @vitaut, that's perfect. Should that file perhaps be "installed" somewhere during the CMakeLists to make complying with the license easier for binary distribution?

[vitaut]

Good point. In fact the CMake configuration for AMPL/MP doesn't have an install target yet as we've been only distributing solver binaries but the library only in source form. I'll look into it.

[tkelman]

An install target would be nice to have :) Having to figure out the list of headers I need to add by trial-and-error isn't much fun. And I'll let you pick the canonical folder you want to put the headers in, to avoid potential .h file naming conflicts.

[vitaut]

OK, I've added the install target and LICENSE.rst is installed in <prefix>/share/mp.

[tkelman]

Cool. Just to let you know the result of my trial-and-error on headers needed by Ipopt and Bonmin was:

src/asl/solvers/asl.h
src/asl/solvers/asl_pfg.h
src/asl/solvers/asl_pfgh.h
src/asl/solvers/psinfo.h
src/asl/solvers/funcadd.h
src/asl/solvers/nlp.h
src/asl/solvers/nlp2.h
src/asl/solvers/getstub.h
src/asl/solvers/opcode.hd
src/asl/solvers/r_opn.hd
src/asl/arith.h
src/asl/stdio1.h

[vitaut]

Oops, looks like I somehow missed quite a few headers including asl.h itself =). Sorry for that. Should be fixed in c086a4e.