[Ipopt] redirection of stdout

Sean Hardesty sean.hardesty at gmail.com
Mon Mar 5 09:15:58 EST 2018

I have a curious issue with Ipopt. I am running on an Ubuntu 16.04 system,
using Ipopt 3.11.9, g++ 5.4, and linking against a bunch of other
libraries, including UMFPACK and CGAL. If I run


it works fine, and I get the expected output, beginning with

This program contains Ipopt, a library for large-scale nonlinear
 Ipopt is released as open source code under the Eclipse Public License
         For more information visit http://projects.coin-or.org/Ipopt

This is Ipopt version 3.11.9, running with linear solver mumps.
NOTE: Other linear solvers might be more efficient (see Ipopt

If my program has called

app->Options()->SetStringValue("output_file", "ipopt.out");

then it also writes the output to ipopt.out. But if I redirect stdout, or
also stderr

my_ipopt_program > run.log
my_ipopt_program > run.log 2>&1

then Ipopt never prints anything to run.log, or to ipopt.out.

Is this behavior expected, a bug, or a problem I have somehow caused?

    Sean Hardesty
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