Version 2.0

New features:

• Coupled heat transfer with new optional dependency on Finch with problem type "FromFinch"
• Optional translation and mirroring of input temperature data (from file or from Finch)
• Support for VTK substrate file input

Performance:

• Minor performance improvement with elimination of redundant memory access and unneeded projection calculations in the cellCapture subroutine

Deprecated features:

• Renamed problem type "C"->"Directional" for directional solidification and "R"->"FromFile" for file-based time-temperature history

Deprecated feature removal:

• Removed support for custom substrate files (VTK now supported)

Bug fixes and improvements:

• Renamed executables and libraries (symlinks to previous executable names)
• Fixed error in the calculation of grain misorientation
• Fixed timers reporting final step time rather than cumulative time
• Added option to disable JSON dependency download ExaCA_REQUIRE_EXTERNAL_JSON
• Split storage of liquidus crossing time and cooling rate to use correct types for each
• Ensure cells cannot go above and below the liquidus on the same step

Version 1.3

New features:

• Object oriented code reorganization
• Removal of restriction to always use default Kokkos::View definitions (however, main executable still uses Kokkos::DefaultExecutionSpace)
• New problem type for single grains growing freely into liquid of input undercooling, thermal gradient and cooling rate

Performance:

• Reduced memory usage and improved CPU/GPU performance by allocating certain structures (such as cell type) only for the current layer of a multilayer simulation, with subviews for other structures (like grain ID). This allows indexing with respect to both the current layer and all layers to be avoided
• Redundant data structures CritTimeStep and MeltTimeStep were removed with an algorithm rewrite for the temperature data, improving GPU performance
• Use of short datatype for LayerID, reducing memory usage and output file size for printing binary data

Deprecated features:

• Support for reading substrate files as the initial condition will be removed in a future release (will be replaced with the ability to read vtk files of GrainID)
• Support for problem type S (arrays of spot melts) will be removed in a future release
• Support for the previous input file print options format will be removed in a future release

Deprecated feature removal:

• Removed support for non-remelting (single case for constrained solidification retained)
• Removed support for plain text (non-JSON) input files

Bug fixes and improvements:

• Removed arbitrary limit on maximum undercooling and growth velocity
• More stable handling of cells that melt and resolidify in rapid succession
• Edge case of incorrect powder layer initialization when the layer height is accounted for in the input thermal data resolved using the new ability to set baseplate top location for multilayer simulations
• Example problems for the new single grain growth problem type
• More flexible and configurable data output for both inter and intralayer details
• Allowed use of temperature data input files that contain additional columns beyond the required x, y, z, tm, tl , cr used by ExaCA (the additional columns are not used by ExaCA, and must appear after the required columns)
• Build system improvements for using ExaCA as a downstream library
• Improved build documentation

Minimum dependency version updates:

• Kokkos 4.0
• nlohmann/json (now required)

Version 1.2

New features:

• Optional JSON input files (main input, material input, and analysis input) and log file (enabled with ExaCA_ENABLE_JSON)
• Optional JSON output files
• Version/commit output functions
• Significant update to analysis routines

Performance:

• Reduced total communication by converting grain ID into separate grain orientation and repeat value which avoids type conversion issues
• Reduce communication buffer sizes from total halo region to the total active communicated cells (plus buffer space)

Deprecated features:

• Problems without remelting with spot arrays and temperature file input
• Plain text input files (main input, material input, and analysis input) and log file

Deprecated feature removal:

• Decomposition strategy as a code input (a 1D domain decomposition in the Y direction is now used for all simulations with multiple MPI ranks)

Bug fixes and improvements:

• Temperature interpolation errors near boundaries
• Nucleation unit test race condition fixed
• Fixed layer height initialization edge case bug that affected the first layer on the baseplate
• Fixed edge case with remelting and rapid cooling/reheating of cells where time step would attempt to fast-forward despite the presence of superheated liquid cells whose solidification had not yet been modeled
• Microstructure analysis moved into separate sub-package

Minimum dependency version updates:

• Kokkos 3.2
• CMake 3.12

New optional dependency:

• nlohmann/json (minimum 3.10)

Version 1.1

New features:

• Added option to include remelting, where multiple melting and liquidus events are used for cells that solidify more than once. Only applicable to spot melts and problems using input time-temperature history data
• Added option to control the density of grains in the powder layer for multilayer simulations

Bug fixes and improvements:

• Fixed bug that caused grain ID values to erroneously change during halo exchange operation for large multilayer problems with a sufficiently large number of grains (fixed with conversion from float to double)
• Added unit tests for coverage across all major portions of ExaCA (initialization, nucleation, cell capture, halo exchange, and output)

Version 1.0

Initial release

Features

• Simulation with Kokkos Serial, OpenMP, Cuda, and HIP backends
• Simulation of directional solidification: grain growth from a surface with a fixed thermal gradient and cooling rate
• Simulation of arrays of overlapping hemispherical spots with fixed thermal gradients and cooling rates
• Simulation with external thermal data for multi-layer additive manufacturing builds
• Grain structure output and analysis routines

Minimum dependency versions

• CMake minimum 3.9 required
• Kokkos minimum 3.0 required
• MPI required