[Coin-ipopt] Announcing Ipopt 3.3.1

Andreas Waechter andreasw at watson.ibm.com
Fri Jun 22 12:24:55 EDT 2007


I finally made a new release that includes the changes we had made in the 
development version of Ipopt.  Since some of the interface functions have 
changes, I also created a new stable branch (now 3.3), since you might 
have to do some minor adjustments to be able to use your C++ code with the 
new Ipopt version.

Here are some highlights of the new release:

- support for the Mumps linear solver (contributed by Damian Hocking)
- --print-options flag for ipopt ASL solver executable to see all
   Ipopt options (available through ipopt.opt file)
   (before, you had to run Ipopt on a problem and specify the
   print_options_documentation option)
- added Matlab interface (contributed by Peter Carbonetto)
   Peter will follow up with a message on this mailing list
- added support for f2c compiler to compile Fortran code with
   MSVC++ compiler.  You no longer need a "native" Fortran compiler (e.g.,
   from Intel) to compile Ipopt.  (Limitation: You cannot use f2c to
   compile Mumps, since that is written in Fortran 90, not Fortran 77)
- new MSVisualStudio support (now within MSVisualStudio project
   and also with f2c)
- an option 'mehrotra_algorithm' which can be used to solve LPs and
   (convex) QPs.  It is an implementation of Mehrotra's predictor-corrector
   algorithm.  However, there is no starting point heuristic.
- a number of small changes/bug fixes/improvements
- small change in interface (e.g., FinalizeSolution method)

Algorithmically, not too much has changed.  There are some new 
undocumented features, such as

- automatic detection of linearly dependent equality constraints which are
   then taken out of the problem (off by default, experimental)
- automatic problem scaling based on equilibration (using MC19)
   (of by default, experimental)

You can already obtain the new release via subversion (svn) from the 
COIN-OR subversion repository.  (If you are using svn, I recommend to 
check out the stable/3.3 branch, since this way you can get new updates 
much easier).  There are also already tarballs for the new release at


Currently, there are problems with the Trac webpages on COIN-OR, so you 
won't be able to submit tickets or edit the wiki pages until this problem 
has been resolved.  But I hope it will be fixed soon.



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