Version 6.17 (2022/11/15)
Highlight: Integrated User Manual
Dakota 6.17 includes a beta version of a new Sphinx-based integrated user manual. It aggregates content from the historical User’s, Theory, and Reference manuals, as well as the Dakota website. Feedback on this new compendium is invited.
Enabling / Accessing: Primarily from https://dakota.sandia.gov, also
Highlight: User Support Moves to Github
External user support is moving to Github Discussions. Discussions offers many advantages over the dakota-users listserv, including threaded conversations, advanced formatting via markdown, LaTeX-formatted mathematical expressions, and more.
We plan to operate dakota-users and the new Discussions forums concurrently until February 15, 2023, when dakota-users will be shut down.
Improvements by Category
Graphical User Interface
Experimental Multi-level/Multi-fidelity UQ editor adds support for ensemble vs. hierarchical surrogate models and has basic estimator performance prediction based on pilot samples.
Allow the experimental Python plugin interface to work correctly as a callback underneath a top-level Dakota Python environment.
Updated version of
pyprepro/dpreproaddresses numerous small issues.
MLMF sampling: Refined sample summary output to distinguish the allocated sample profile from the successfully evaluated samples, clarifying the final results. These counts may differ in the presence of solution_mode pilot_projection, final_statistics estimator_performance, or simulation fault tolerance.
MLMF sampling: For fault tolerant sampling, allocations no longer backfill for simulation failures by default (reflecting the observation that simulation faults are almost always biased in the parameter space, and backfill amplifies this bias.)
MLMF sampling: For numerical solutions in ACV and MFMC based on solving optimization subproblems, add support for minimizing total cost with respect to an accuracy constraint and support these alternate objective/constraint definitions within bi-level model tuning.
MLMF sampling: Hardened online cost recovery for edge cases.
Update (experimental) MUQ package for Bayesian calibration
New Sphinx-based documentation infrastructure unifies historical manuals and permits building the Dakota documentation on its own or as part of a CMake-based Dakota build.
Miscellaneous Enhancements and Bugfixes
Enh: Make build system more tolerant of HDF5/h5py variants when registering unit tests. Allow working with h5py 3.0+.
Enh: Routine testing on RHEL8 operating system with system-default compilers and tools.
Enh: Console output/errors are more reliably and consistently redirected when options are given in the input file. (Most TPL-generated output will still not appear in them however).
Enh: Restart file versioning. Restart files now have embedded version information and will attempt to detect whether an imported file is compatible.
Enh: Refined check for zero variance QoIs and other cases that could lead to numerical exceptions, e.g., in calculating Sobol’ indices.
Enh: Enable exporting PCE coefficients when using in Bayesian calibration.
Bug fix: MLMF UQ methods properly generate tabular output for concurrent evaluations
Bug fix: Dakota should now compile when using a C++17-compliant compiler. (Thanks to Heidi Thornquist for reporting and testing.)
Bug fix: Properly map inactive variables through subspace models, notably discrete string variables.
Deprecated and Changed
Dakota no longer supports Python 2 for Dakota-provided Python utilities such as dprepro or dakota.interfacing, though tools may continue to work for some time.
Migrated to std C++ random number generators and distribution utilities in a number of places in Dakota and associate TPLs. This favored over rand()/srand() and Boost utilities. Will break reproducibility of specific sample sets w.r.t. historical Dakota versions, even on the same architecture and toolchain.
Future (post-6.17) Dakota releases will require a C++14-compliant compiler and will only be tested on gcc-8.5.0 and newer (and similar vintage) compilers.
LaTeX is no longer required to build default versions of Dakota manuals.
CMake 3.17 or newer is required to compile Dakota
Sphinx and associated plugins are required for building the new integrated user manual.
Java 11 JDK is required for documentation generation and input specification maintenance.
Doxygen 1.8.20 is required for building the developer manual.
No changes to minimum C++11 compiler requirement, Boost 1.69, or required/optional external TPLs.
Other Notes and Known Issues