[Ipopt] Restoration phase is called at point that is almost feasible, with constraint violation 4.202374e-007

[Ali Baharev]

Hello Everyone,

Please let me start with declaring that I am a great fan of the
restoration phase in IPOPT.

I am writing a research paper demonstrating how powerful and robust it
is: it can solve problems that are difficult or even (practically)
impossible to solve with other state-of-the-art commercial solvers!

I do not have the time to have a look at each of these problems but
they may have a common cause:

http://list.coin-or.org/pipermail/ipopt/2009-July/001646.html

In the announcement

http://list.coin-or.org/pipermail/ipopt/2009-November/001732.html

the above issue is said to be solved by "loosening the termination
tolerance for the restoration phase problem" but it seems to me a
workaround. Why did a strict termination work just fine in 3.6.1?

http://list.coin-or.org/pipermail/ipopt/2010-January/001845.html

http://list.coin-or.org/pipermail/ipopt/2010-January/001847.html

http://list.coin-or.org/pipermail/ipopt/2010-January/001853.html

Developers, please check if it was not a change in the restoration
phase that causes the above issues.

I will test the new version of IPOPT on my benchmark set in the next
couple of weeks and see that the restoration phase is still as robust
as it was in 3.6.1.

Thanks,

Ali