[Coin-ipopt] Announcing new release Ipopt 3.1.0

[Andreas Waechter]

I'm very happy to announce that we finally finished a new major
release of Ipopt (version 3.1.0).

Beside a number of bug fixes, improvements and additions, the new
features include:

- A Quasi-Newton option (based on limited memory BFGS) to approximate
   the Hessian of the Lagrangian function.  This can now be used if
   second derivatives are not available.

- New interfaces to additional linear solvers (besides MA27):
   * Harwell subroutine MA57
   * Parallel Sparse Direct Solver PARDISO
   * Watson Sparse Matrix Package WSMP

- A simple derivative checker, which allows a convenient verification
   of user-coded first and second derivatives.

- The option to use a call-back method to monitor the optimization
   progress and request an early termination if desired (so far for C++
   interface only).

- A simple unit test ("make test") to verify successful installation.

- The option to compile Ipopt with native compilers (MS VC++ and Intel
   Fortran) under Cygwin.


If you have been using the previous version of Ipopt, you might have
to make a few modifications for the new release.  In particular:

- The names and default values for some options have changed and new
   options have been added.

- The options file for Ipopt is now called "ipopt.opt" (previously
   "PARAMS.DAT").

- If you are using the C++ interface, you need to call the
   "Initialize" method of the "IpoptInterface" class before calling an
   "Optimize" method.

- If you want to use the quasi-Newton option, you will have to obtain
   LAPACK.


Thanks go to:

- Carl Laird (CMU) for many bug fixes and improvements.

- Michael Hagemann and Olaf Schenk (University of Basel) for adapting
   Pardiso for the needs of Ipopt and for contributing the Pardiso
   interface.

- Anshul Gupta (IBM Research) for implementing an indefinite symmetric
   solver in WSMP.

and also to many users who helped us to improve Ipopt with their
valuable bug reports, bug fixes, comments and suggestions.


I want to use this opportunity also to point out that the Ipopt
project home page at

http://projects.coin-or.org/Ipopt

is based on the Wiki system, and is not only for reading, but actually
also for writing!  ;)  We encourage you to share your experiences or
tricks with other users, and to tell the world what you are using
Ipopt for...


The new version is available from the COIN-OR subversion repository
(if you have subversion installed on your system - this is the
recommended way) via the UNIX/Linux command

svn co https://www.coin-or.org/svn/Ipopt/trunk Ipopt

(or just with "svn update" in your local repository copy if you have
one)

and will be available as tarball starting tomorrow from

http://www.coin-or.org/Tarballs/ipopt-3.1.0.tar.gz


Regards,

Andreas