[Ipopt] Announcing Ipopt 3.8.1

[Andreas Waechter]

Hi,

I would like to annouce a new Ipopt release (3.8.1).

The main addition is now a Microsoft Deverloper Studio solution 
(contributed by Marcel Roelofs - thanks!!!!) that is able to build an 
Ipopt DLL for Windows.

This will make it much easier to use Ipopt on Windows, since Marcel will 
also provide precompiled version of the DLL at

http://www.coin-or.org/download/binary/Ipopt/

This DLL includes the public domain solver MUMPS, but using the "library 
loader" that and already been contributed previously by Stefan Vigerske, a 
Pardiso DLL or a DLL with Harwell subroutines (which the user has to 
compile) can be loaded at runtime.

A lot of messages on the Ipopt mailing list had to do with having trouble 
to compile Ipopt on Windows.  This will hopefully make it much easier for 
Windows users to make use of Ipopt in their projects.

One technical issue is that if you are using Ipopt from C++ and you want 
to use the DLL, you need to obtain the IpoptApplication pointer with the 
new IpoptApplicationFactory() function.  The examples have been adapted to 
include this change already.

Other than this, there were only a few minor changes:

- loosening the termination tolerance for the restoration phase problem;
   in some examples it seemed that the previous setting was too tight and
   Ipopt did not terminate for infeasible problems.
- there was a mistake in the CPU time measurements for NLP function
   evaluations, the time for computing the objective function gradient had
   been ignored.

Regards,

Andreas