Release Notes for Dymos 1.10.0
December 08, 2023
Dymos 1.10.0 includes a few performance improvements, more user-configurability of automatic solver placement, and a still-experimental implementation of the Birkhoff transcription.
Thanks to Shugo Kaneko for pointing out some issues with using dymos under MPI.
Timeseries jacobians were inefficient and used excessive memory when operating on a single system under MPI.
Also, the user now has more control over how solvers are added when necessary. Previously, the presence of a DirectSolver over a distributed system was causing an error.
Trajectory now has a parallel_phases option. When True (the default), the top level Trajectory.phases container will be an OpenMDAO ParallelGroup. Setting it to False makes Trajectory.phases a standard serial OpenMDAO.api.Group object.
Trajectory and Phase now both have an auto_solvers option. It is enabled by default and will result in appropriate nonlinear and linear solvers being placed when it is True.
Trajectory.phases needs a nonlinear solver when running phases in parallel under MPI AND the phases are directly connected.
Phases need a solver when there is implicit behavior due to a duration balance or the use of solve_segments is pseudospectral phases.
Backwards Incompatible API Changes & Deprecations
- None
Enhancements
- Reduce memory usage for timeseries jac computation #1001
- Added Birkhoff Transcription (this feature is still somewhat experimental) #1008 #1010 #1021
Bug Fixes
- Fixed python 3.12 compatibility issues. #1004
- Fixed load_case logic to correctly handle negative-duration phases #1007
- Boundary constraints in Birkhoff transcription changed to pull from boundary ODE #1018
- Fixed an issue where applying DirectSolver to StateIndependentsComp was breaking when used with other linear solvers under MPI. #1020
- Fixed Vanderpol example under updated OpenMDAO MPI operation. #1023