= Welcome to the Ipopt home page =
''Note that these project webpages are based on Wiki, which allows webusers to modify the content to correct typos, add information, or share their experience and tips with other users. You are welcome to contribute to these project webpages. To edit these pages or submit a ticket you must first [http://www.coin-or.org/usingTrac.html register and login].''
== Introduction ==
Ipopt ('''I'''nterior '''P'''oint '''OPT'''imizer, pronounced eye-pea-Opt) is a software package for large-scale [http://wiki.mcs.anl.gov/NEOS/index.php/Nonlinear_Programming_FAQ nonlinear optimization]. It is designed to find (local) solutions of mathematical optimization problems of the from
{{{
min f(x)
x in R^n
s.t. g_L <= g(x) <= g_U
x_L <= x <= x_U
}}}
where
{{{ f(x): R^n --> R }}}
is the objective function, and
{{{ g(x): R^n --> R^m }}}
are the constraint functions. The vectors {{{ g_L }}} and {{{ g_U }}} denote the lower and upper bounds on the constraints, and the vectors {{{x_L}}} and {{{x_U}}} are the bounds on the variables {{{x}}}. The functions {{{f(x)}}} and {{{g(x)}}} can be nonlinear and nonconvex, but should be twice continuously differentiable. Note that equality constraints can be formulated in the above formulation by setting the corresponding components of {{{g_L}}} and {{{g_U}}} to the same value.
Ipopt is part of the [http://www.coin-or.org/ COIN-OR Initiative].
== Background ==
Ipopt is written in C++ and is released as open source code under the Eclipse Public License (EPL). It is available from the [http://www.coin-or.org/ COIN-OR initiative]. The code has been written by [http://www.mccormick.northwestern.edu/directory/profiles/Andreas-Waechter.html Andreas Wächter] and [http://www.che.tamu.edu/people/faculty/info?fid=73 Carl Laird]. The COIN-OR project managers for Ipopt are [http://users.iems.northwestern.edu/~andreasw Andreas Wächter] und [http://www.math.hu-berlin.de/~stefan/ Stefan Vigerske].
For a list of **all contributors**, see the [browser:trunk/Ipopt/AUTHORS AUTHORS file].
The C++ version has first been [http://list.coin-or.org/pipermail/ipopt/2005-August/000331.html released on Aug 26, 2005] as version 3.0.0.
The previously released [http://www.coin-or.org/Ipopt/ipopt-fortran.html pre-3.0 Fortran version] is no longer maintained.
The Ipopt distribution can be used to generate a library that can be linked to one's own C++, C, Fortran, or Java code, as well as a solver executable for the [http://www.ampl.com AMPL] modeling environment. The package includes interfaces to [http://cuter.rl.ac.uk/cuter-www/ CUTEr] optimization testing environment, as well as the [http://www.mathworks.com/products/matlab MATLAB] and [http://www.r-project.org/ R] programming environments. IPOPT can be used on Linux/UNIX, Mac OS X and Windows platforms.
As open source software, the source code for Ipopt is provided without charge. You are free to use it, also for commercial purposes. You are also free to modify the source code (with the restriction that you need to make your changes public if you decide to distribute your version in any way, e.g. as an executable); for details see the EPL license. And we are certainly very keen on feedback from users, including contributions!
In order to compile Ipopt, certain third party code is required (such as some linear algebra routines). Those are available under different conditions/licenses.
If you want to learn more about Ipopt, you can find references in the [http://www.coin-or.org/Ipopt/documentation/node63.html bibliography of the documentation] and the [wiki:IpoptPapers "Papers about Ipopt" page].
For information on projects that use Ipopt, refer to the [wiki:SuccessStories Success Stories page].
== Download ==
'''[http://www.coin-or.org/download/source/Ipopt Download Ipopt source as tarballs.]'''
You can also obtain the Ipopt code via Subversion. Please refer to the [http://www.coin-or.org/Ipopt/documentation/ documentation] and the [https://projects.coin-or.org/CoinHelp/ General Configuration and Installation Instructions for COIN-OR projects].
'''Please make sure you read the [https://projects.coin-or.org/CoinHelp/wiki/current-issues current issues page] before you try to install Ipopt.'''
Also still available is the no longer maintained older [http://www.coin-or.org/Ipopt/ipopt-fortran.html Fortran version].
'''[http://www.coin-or.org/download/binary/Ipopt/ Download Ipopt binaries]''' (including mex files for use in '''MATLAB''').
== Documentation and Support ==
The '''[http://www.coin-or.org/Ipopt/documentation/ main Ipopt documentation]''' is available as [http://www.coin-or.org/Ipopt/documentation/ HTML] and [browser:stable/3.11/Ipopt/doc/documentation.pdf?format=raw PDF]. It contains
* '''[http://www.coin-or.org/Ipopt/documentation/node10.html Installation Instructions]'''
* [http://www.coin-or.org/Ipopt/documentation/node12.html Getting Ipopt code] and
[http://www.coin-or.org/Ipopt/documentation/node13.html 3rd party code]
* '''[http://www.coin-or.org/Ipopt/documentation/node14.html Compiling Ipopt]'''
([http://www.coin-or.org/Ipopt/documentation/node15.html under Windows])
* '''[http://www.coin-or.org/Ipopt/documentation/node16.html Java Interface]'''
* '''[http://www.coin-or.org/Ipopt/documentation/node17.html R Interface]'''
* '''[http://www.coin-or.org/Ipopt/documentation/node18.html MATLAB Interface]'''
* [http://www.coin-or.org/Ipopt/documentation/node19.html Expert Installation Options]
* '''[http://www.coin-or.org/Ipopt/documentation/node20.html Interfacing Ipopt]'''
* [http://www.coin-or.org/Ipopt/documentation/node21.html AMPL]
* [http://www.coin-or.org/Ipopt/documentation/node22.html Code]:
[http://www.coin-or.org/Ipopt/documentation/node23.html C++],
[http://www.coin-or.org/Ipopt/documentation/node24.html C],
[http://www.coin-or.org/Ipopt/documentation/node25.html Fortran],
[http://www.coin-or.org/Ipopt/documentation/node26.html Java]
* [http://www.coin-or.org/Ipopt/documentation/node27.html R]
* [http://www.coin-or.org/Ipopt/documentation/node28.html MATLAB]
* '''Special Features''':
* [http://www.coin-or.org/Ipopt/documentation/node30.html Derivative Checker]
* [http://www.coin-or.org/Ipopt/documentation/node31.html Hessian Approximation]
* [http://www.coin-or.org/Ipopt/documentation/node32.html Warm starts via AMPL]
* [http://www.coin-or.org/Ipopt/documentation/node33.html sIpopt: Optimal Sensitivity Based on AMPL/Ipopt]
* '''[http://www.coin-or.org/Ipopt/documentation/node35.html Output]'''
* [http://www.coin-or.org/Ipopt/documentation/node34.html Option Files],
'''[http://www.coin-or.org/Ipopt/documentation/node39.html Options Reference]''',
[http://www.coin-or.org/Ipopt/documentation/node62.html Options available via AMPL]
Further Information:
* '''[wiki:FAQ FAQ]''' (Frequently Asked Questions)
* '''[http://list.coin-or.org/pipermail/ipopt/ Mailing list archive]'''
* '''[wiki:CompilationHints Compilation hints]''' collected by users (partly outdated)
* '''[https://projects.coin-or.org/CoinHelp/wiki/current-issues Current configuration and installation issues]''' for COIN-OR projects
* [https://projects.coin-or.org/CoinHelp/ General Configuration and Installation Instructions] for COIN-OR projects
* [http://drops.dagstuhl.de/volltexte/2009/2089/pdf/09061.WaechterAndreas.Paper.2089.pdf short Ipopt tutorial]
* [wiki:HintsAndTricks Hints and tricks] on using Ipopt
* [http://www.coin-or.org/Ipopt/doxygen Doxygen documentation for the Ipopt source code] can be generated by executing {{{make doxydoc}}} in an Ipopt build directory
Getting Help:
* '''[http://list.coin-or.org/mailman/listinfo/ipopt Mailing list]''': subscribe to get notifications about updates and to post questions and comments regarding Ipopt
* '''[http://projects.coin-or.org/Ipopt/report Bug report system]''': If you believe you found a '''bug''' in the code, please use the bug report system (see the [http://projects.coin-or.org/Ipopt/report "View Tickets"] and [http://projects.coin-or.org/Ipopt/newticket "New Ticket"] tabs on put of this page). [[BR]]
Please include as much information as possible, and if possible some (ideally simple) example code so that we can reproduce the error. Note that you will have to log in first, as described [wiki:EditingWikiPages here].
== Related Projects ==
'''[https://projects.coin-or.org/ADOL-C COIN-OR/ADOL-C]''': Using Ipopt via '''C++''' and automatic differentiation ([https://projects.coin-or.org/ADOL-C/browser/stable/2.4/ADOL-C/examples/additional_examples/ipopt examples]).
'''[https://projects.coin-or.org/AIMMSlinks COIN-OR/AIMMSlinks]''': Using Ipopt via '''AIMMS'''
'''[https://projects.coin-or.org/CppAD COIN-OR/CppAD]''': Using Ipopt via '''C++''' and automatic differentiation ([http://www.coin-or.org/CppAD/Doc/ipopt_solve.htm example]).
'''[https://projects.coin-or.org/GAMSlinks COIN-OR/GAMSlinks]''': Using Ipopt via '''GAMS'''
'''[https://projects.coin-or.org/OS COIN-OR/Optimization Services]''': Using Ipopt via '''OS'''
'''[https://github.com/casadi/casadi/wiki CasADi]''': Using Ipopt in a symbolic framework for automatic differentiation and numeric optimization.
'''[http://code.google.com/p/csipopt/ csipopt]''': Interfacing Ipopt from .NET languages such as '''C#''', '''F#''' and '''Visual Basic.NET'''.
'''[https://github.com/JuliaOpt/JuMP.jl JuMP]''': Algebraic modeling with automatic differentiation in '''Julia''' ([https://github.com/JuliaOpt/Ipopt.jl low-level interface] also available)
'''[http://www.i2c2.aut.ac.nz/Wiki/OPTI/ OPTI Toolbox]''': Windows x86 + x64 '''MATLAB''' Interface, including binaries
'''[http://code.google.com/p/pyipopt/ pyipopt]''': Interfacing Ipopt from '''Python'''
'''[http://forge.scilab.org/index.php/p/sci-ipopt sci-ipopt]''': Interfacing Ipopt from '''Scilab''' (a free MATLAB-like environment)
== Please Cite Us ==
We provide this program in the hope that it may be useful to others, and we would very much like to hear about your experience with it. If you found it helpful and are using it within our software, we encourage you to add your feedback to the [wiki:SuccessStories Success Stories page].
Since a lot of time and effort has gone into Ipopt's development, '''please cite the following publication if you are using Ipopt for your own research''':
* A. Wächter and L. T. Biegler, '''[http://dx.doi.org/10.1007/s10107-004-0559-y On the Implementation of a Primal-Dual Interior Point Filter Line Search Algorithm for Large-Scale Nonlinear Programming]''', ''Mathematical Programming'' 106(1), pp. 25-57, 2006[[BR]]
([http://www.optimization-online.org/DB_HTML/2004/03/836.html preprint])