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Condor

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,

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:

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 the child models. For example, we can optimize this coupled algebraic system, with an OptimizationProblem model,

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 + exp(-y2)
    constraint(y1 >= 3.16)
    constraint(24. >= y2)

This optimizaiton problem can be solved and the sub-model can be accessed directly:

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

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

Installation

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

$ pip install condor

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

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