[Ipopt] Empty solution in funcs.iterfunc using Matlab wrapper

[Tony Kelman]

Xinhua,

I believe this can happen during restoration phase or some other condition 
that causes one of the IpoptCalculatedQuantities, OrigIpoptNLP, TNLPAdapter, 
or IpoptData to be NULL, or the IpoptData to not be valid. We'd have to see 
a test case to determine exactly what the cause is. The relevant section of 
the code is lines 422-432 of 
Ipopt/contrib/MatlabInterface/src/callbackfunctions.cpp, perhaps Stefan may 
be more familiar with the algorithm steps that can lead to these conditions?

-Tony


-----Original Message----- 
Date: Mon, 29 Jul 2013 02:50:10 +1000
From: "Xinhua Zhang" <xinhua.zhang at nicta.com.au>
To: <ipopt at list.coin-or.org>
Subject: [Ipopt] Empty solution in funcs.iterfunc using Matlab wrapper

Hi All,

I am using the Matlab mex of IPOPT for 64-bit Windows, which was downloaded
directly from the web site.  In the funcs.iterfunc callback, the x field of
the third argument (which is supposed to be the current solution), becomes
an empty matrix after two iterations (ie after funcs.iterfunc has been
successfully called for two times):

ans =

                      x: []
                 inf_pr: 11.3335
                 inf_du: 999.0005
                     mu: 11.3335
                 d_norm: 0
    regularization_size: 0
               alpha_du: 0
               alpha_pr: 2.2737e-13
              ls_trials: 40

x was not empty in the first two iterations.  Does anyone know the cause
and/or a solution?

Thanks a lot.

Xinhua