SUNDIALS v5.8.0

Changes to SUNDIALS in release 5.8.0

The RAJA NVECTOR implementation has been updated to support the SYCL backend in addition to the CUDA and HIP backend. Users can choose the backend when configuring SUNDIALS by using the SUNDIALS_RAJA_BACKENDS CMake variable. This module remains experimental and is subject to change from version to version.

A new SUNMatrix and SUNLinearSolver implementation were added to interface with the Intel oneAPI Math Kernel Library (oneMKL). Both the matrix and the linear solver support general dense linear systems as well as block diagonal linear systems. This module is experimental and is subject to change from version to version.

Added a new optional function to the SUNLinearSolver API, SUNLinSolSetZeroGuess, to indicate that the next call to SUNlinSolSolve will be made with a zero initial guess. SUNLinearSolver implementations that do not use the SUNLinSolNewEmpty constructor will, at a minimum, need set the setzeroguess function pointer in the linear solver ops structure to NULL. The SUNDIALS iterative linear solver implementations have been updated to leverage this new set function to remove one dot product per solve.

The time integrator packages (ARKODE, CVODE(S), and IDA(S)) all now support a new "matrix-embedded" SUNLinearSolver type. This type supports user-supplied SUNLinearSolver implementations that set up and solve the specified linear system at each linear solve call. Any matrix-related data structures are held internally to the linear solver itself, and are not provided by the SUNDIALS package.

Added functions to ARKODE and CVODE(S) for supplying an alternative right-hand side function and to IDA(S) for supplying an alternative residual for use within nonlinear system function evaluations.

Support for user-defined inner (fast) integrators has been to the MRIStep module in ARKODE. See the "MRIStep Custom Inner Steppers" section in the user guide for more information on providing a user-defined integration method.

Added specialized fused HIP kernels to CVODE which may offer better performance on smaller problems when using CVODE with the NVECTOR_HIP module. See the optional input function CVodeSetUseIntegratorFusedKernels for more information. As with other SUNDIALS HIP features, this is feature is experimental and may change from version to version.

New KINSOL options have been added to apply a constant damping factor in the fixed point and Picard iterations (see KINSetDamping), to delay the start of Anderson acceleration with the fixed point and Picard iterations (see KINSetDelayAA), and to return the newest solution with the fixed point iteration (see KINSetReturnNewest).

The installed SUNDIALSConfig.cmake file now supports the COMPONENTS option to find_package. The exported targets no longer have IMPORTED_GLOBAL set.

A bug was fixed in SUNMatCopyOps where the matrix-vector product setup function pointer was not copied.

A bug was fixed in the SPBCGS and SPTFQMR solvers for the case where a non-zero initial guess and a solution scaling vector are provided. This fix only impacts codes using SPBCGS or SPTFQMR as standalone solvers as all SUNDIALS packages utilize a zero initial guess.

A bug was fixed in the ARKODE stepper modules where the stop time may be passed after resetting the integrator.

A bug was fixed in IDASetJacTimesResFn in IDAS where the supplied function was used in the dense finite difference Jacobian computation rather than the finite difference Jacobian-vector product approximation.

A bug was fixed in the KINSOL Picard iteration where the value of KINSetMaxSetupCalls would be ignored.