Condor, a mathematical modeling framework for engineers with deadlines

Condor, a mathematical modeling framework for engineers with deadlines - Published in JOSS (2025)

https://github.com/nasa/condor

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NASA's Condor is a framework for mathematical modeling of engineering systems in Python, for engineers with deadlines.

README.rst

Condor
======

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Condor is a new mathematical modeling framework for Python, developed at
NASA's Ames Research Center. Initial development began in April 2023 to
address model implementation challenges for aircraft synthesis and
robust orbital trajectory design. The goal is for Condor to help
evaluate numerical models and then get out of the way.

One key aspect to achieve this goal was to create an API that looked as
much like the mathematical description as possible with as little
distraction from programming cruft as possible. To best understand
this approach, we can consider a simple benchmark problem which consists
of a set of coupled algebraic expressions. This can be represented as a
system of algebraic equations:

.. code-block:: python

  import condor as co

  class Coupling(co.AlgebraicSystem):
      x = parameter(shape=3)
      y1 = variable(initializer=1.)
      y2 = variable(initializer=1.)

      residual(y1 == x[0] ** 2 + x[1] + x[2] - 0.2 * y2)
      residual(y2 == y1**0.5 + x[0] + x[1])

This parametric model can be evaluated by providing the values for the
parameters; the resulting object has values for its inputs and outputs
bound, so the solved values for ``y1`` and ``y2`` can be accessed easily:

.. code-block:: python

   coupling = Coupling([5., 2., 1]) # evaluate the model numerically
   print(coupling.y1, coupling.y2) # individual elements are bound numerically
   print(coupling.variable) # fields are bound as a dataclass

Models can also be seamlessly built-up, with parent models accessing any
input or output of models embedded within them. For example, we can
optimize this system of algebraic equations by embedding it within an
optimization problem:

.. code-block:: python

  from condor.backend import operators as ops

  class Sellar(co.OptimizationProblem):
      x = variable(shape=3, lower_bound=0, upper_bound=10)
      coupling = Coupling(x)
      y1, y2 = coupling

      objective = x[2]**2 + x[1] + y1 + ops.exp(-y2)
      constraint(y1 >= 3.16)
      constraint(24. >= y2)

After the model is solved, the embedded model can be accessed directly:

.. code-block:: python

   Sellar.set_initial(x=[5,2,1])
   sellar = Sellar()
   print(sellar.objective) # scalar value
   print(sellar.constraint) # field
   print(sellar.coupling.y1) # embedded model element

NASA's Condor is a framework for mathematical modeling of engineering
systems in Python, written for engineers with deadlines.

Installation
------------

Condor is available on `PyPI `_, so you can
install with pip:

.. code:: bash

   pip install condor

Optionally, you can include the dependencies to run the examples:

.. code:: bash

   pip install condor[examples]

Contributing
------------

Please feel free to share any thoughts or opinions about the design and
implementation of this software by `opening an issue on GitHub
`_. Constructive feedback is
welcomed and appreciated.

Bug fix pull requests are always welcome. For feature additions, breaking
changes, etc. check if there is an open issue discussing the change and
reference it in the pull request. If there isn't one, it is recommended to open
one with your rationale for the change before spending significant time
preparing the pull request.

Ideally, new/changed functionality should come with tests and documentation. If
you are new to contributing, it is perfectly fine to open a work-in-progress
pull request and have it iteratively reviewed.

For pull requests to be accepted, all contributors must have a contributor's
agreement on file with NASA. We will provide contributors with additional
information during the review process.

Development
^^^^^^^^^^^

Clone the repository and install it in editable mode along with the ``dev``
dependency group in a virtual environment:

.. code:: bash

    pip install --upgrade pip
    pip install -e . --group dev

A `pre-commit `_ configuration is available to
automatically format and fix linting issues when creating a commit. Install
pre-commit either in the virtual environment created above or as a system-wide
tool (e.g. pipx or uv tool), then install the hooks:

.. code:: bash

    pre-commit install

The first run of the hooks will take a few seconds as the isolated environments
are created. Subsequent runs will generally be much faster.

To run the tests, run::

    pytest


License
-------

This software is released under the `NASA Open Source Agreement Version 1.3
`_.

Notices
-------

Copyright © 2024 United States Government as represented by the Administrator of
the National Aeronautics and Space Administration.  All Rights Reserved.

Disclaimers
-----------

No Warranty: THE SUBJECT SOFTWARE IS PROVIDED "AS IS" WITHOUT ANY WARRANTY OF
ANY KIND, EITHER EXPRESSED, IMPLIED, OR STATUTORY, INCLUDING, BUT NOT LIMITED
TO, ANY WARRANTY THAT THE SUBJECT SOFTWARE WILL CONFORM TO SPECIFICATIONS, ANY
IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, OR
FREEDOM FROM INFRINGEMENT, ANY WARRANTY THAT THE SUBJECT SOFTWARE WILL BE ERROR
FREE, OR ANY WARRANTY THAT DOCUMENTATION, IF PROVIDED, WILL CONFORM TO THE
SUBJECT SOFTWARE. THIS AGREEMENT DOES NOT, IN ANY MANNER, CONSTITUTE AN
ENDORSEMENT BY GOVERNMENT AGENCY OR ANY PRIOR RECIPIENT OF ANY RESULTS,
RESULTING DESIGNS, HARDWARE, SOFTWARE PRODUCTS OR ANY OTHER APPLICATIONS
RESULTING FROM USE OF THE SUBJECT SOFTWARE.  FURTHER, GOVERNMENT AGENCY
DISCLAIMS ALL WARRANTIES AND LIABILITIES REGARDING THIRD-PARTY SOFTWARE, IF
PRESENT IN THE ORIGINAL SOFTWARE, AND DISTRIBUTES IT "AS IS."

Waiver and Indemnity:  RECIPIENT AGREES TO WAIVE ANY AND ALL CLAIMS AGAINST THE
UNITED STATES GOVERNMENT, ITS CONTRACTORS AND SUBCONTRACTORS, AS WELL AS ANY
PRIOR RECIPIENT.  IF RECIPIENT'S USE OF THE SUBJECT SOFTWARE RESULTS IN ANY
LIABILITIES, DEMANDS, DAMAGES, EXPENSES OR LOSSES ARISING FROM SUCH USE,
INCLUDING ANY DAMAGES FROM PRODUCTS BASED ON, OR RESULTING FROM, RECIPIENT'S USE
OF THE SUBJECT SOFTWARE, RECIPIENT SHALL INDEMNIFY AND HOLD HARMLESS THE UNITED
STATES GOVERNMENT, ITS CONTRACTORS AND SUBCONTRACTORS, AS WELL AS ANY PRIOR
RECIPIENT, TO THE EXTENT PERMITTED BY LAW.  RECIPIENT'S SOLE REMEDY FOR ANY SUCH
MATTER SHALL BE THE IMMEDIATE, UNILATERAL TERMINATION OF THIS AGREEMENT.

Owner

JOSS Publication

Condor, a mathematical modeling framework for engineers with deadlines

Published

September 16, 2025

DOI

10.21105/joss.08859

Volume 10, Issue 113, Page 8859

Authors

Benjamin W. l. Margolis
NASA Ames Research Center, Systems Analysis Office

Kenneth R. Lyons
NASA Ames Research Center, Systems Analysis Office

Editor

Daniel S. Katz

Tags

mathematical modeling optimization metaprogramming domain-specific language

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