Release Notes#

cuDSS v0.7.1#

New Features:

  • Enabled CUDSS_DATA_USER_ELIMINATION_TREE: It can be used in combination with CUDSS_DATA_USER_PERM to set both the user permutation and elimination tree with values from a previous run, maintaining the factorization and solve performance while improving the reordering time.

Important bug fixes:

  • Fixed performance regression in the reordering phase with the default reordering algorithm for matrices with block structure (also known as BSR) (CUDSS-1035).

Known issues:

  • Changing the data type of the matrix while reusing an existing cudssHandle_t will not lead to correct results and might crash (CUDSS-1019).

  • Matrices with more than \(2^{31}\) rows or columns are not supported.

  • compute-sanitizer might report spurious uninitialized read on Windows in multi-GPU (MG) mode (CUDSS-1026). Please report if observed.

  • On Linux, depending on the version of GNU OpenMP runtime, valgrind and sanitizer tools may crash or report a memory leak during the call to cudssDestroy() if multi-threaded mode is used (CUDSS-1079). This happens when cuDSS is calling dlclose() for the multi-threading layer library and is caused by GNU OpenMP runtime unloading. As a workaround, set GOMP_SPINCOUNT to 0 in the environment or add a call to dlopen() for the libgomp.so shared library in the application (before calling cudssDestroy()).

  • Reordering algorithm CUDSS_ALG_3 may crash on very small matrices (CUDSS-1030)

  • Separate calls to CUDSS_PHASE_REORDERING and CUDSS_PHASE_SYMBOLIC_FACTORIZATION with matrix types other than CUDSS_MTYPE_GENERAL with matching enabled produce incorrect results (CUDSS-1070). As a workaround, use CUDSS_PHASE_ANALYSIS.

cuDSS v0.7.0#

New Features:

  • Enabled multi-GPU single-node (MG) mode via cudssCreateMg() and CUDSS_CONFIG_DEVICE_COUNT and CUDSS_CONFIG_DEVICE_INDICES

  • Re-introduced factorization algorithm CUDSS_ALG_1 with improved performance for matrices with very sparse factors

  • Added support for int64_t indexing for sparse matrices

  • Enabled turning on and off superpanel optimization (CUDSS_CONFIG_USE_SUPERPANELS)

  • Enabled extracting the auxiliary elimination tree structure (CUDSS_DATA_ELIMINATION_TREE)

  • Added support for solve sub-phases (CUDSS_PHASE_SOLVE_FWD, CUDSS_PHASE_SOLVE_FWD_PERM, CUDSS_PHASE_SOLVE_BWD, CUDSS_PHASE_SOLVE_BWD_PERM)

  • Added support for Schur complement mode (CUDSS_CONFIG_SCHUR_MODE, CUDSS_DATA_USER_SCHUR_INDICES, CUDSS_DATA_SCHUR_SHAPE, CUDSS_DATA_SCHUR_MATRIX)

  • Added support for deterministic mode (CUDSS_CONFIG_DETERMINISTIC_MODE)

  • Enabled user interruption on the host (CUDSS_DATA_USER_HOST_INTERRUPT)

  • Improved performance for the symbolic factorization phase with CUDSS_ALG_DEFAULT and CUDSS_ALG_3 reordering algorithms

  • Enabled support for CUDA 13 and new Blackwell GPU architectures (incl. GB300 and DGX Spark)

Breaking changes:

  • All user provided data (provided with the prefix CUDSS_DATA_USER_) is now copied to an internal buffer with a cudssDataSet operation and copied back with a cudssDataGet operation. This breaks the call of cudssDataGet with CUDSS_DATA_USER_PERM as it now copies the data to the provided pointer instead of copying the pointer.

Important bug fixes:

  • Fixed incorrect results for the default matching algorithm for hybrid memory mode and hybrid execute mode, when the scaling vectors are non-constant (CUDSS-882).

  • Fixed the crash when in MGMN mode some of the ranks have empty local parts of the matrix (CUDSS-913).

  • Fixed out-of-bounds access during reordering for very large matrices (CUDSS-948).

  • Fixed incorrect results for symmetric matrices with superpanel and pivoting options enabled (CUDSS-1003).

Known issues:

  • Setting CUDSS_DATA_USER_ELIMINATION_TREE is currently not supported and leads to undefined behavior (CUDSS-1020).

  • Changing the data type of the matrix while reusing an existing cudssHandle_t will not lead to correct results and might crash (CUDSS-1019)

  • Matrices with more than \(2^{31}\) rows or columns are not supported.

  • compute-sanitizer might report spurious uninitialized read on Windows in multi_GPU (MG) mode (CUDSS-1026)

  • Performance regression on reordering phase with the default reordering algorithm for matrices with block structure (aka BSR) (CUDSS-1035)

cuDSS v0.6.0#

New Features:

  • Enabled support for distributed matrices with a row-wise potentially overlapping distribution via cudssMatrixSetDistributionRow1d()

  • Enabled support for matching and scaling with CUDSS_CONFIG_USE_MATCHING and CUDSS_CONFIG_MATCHING_ALG

  • Enabled support for solving uniform batches (same sparsity pattern) of linear systems via CUDSS_CONFIG_UBATCH_SIZE and CUDSS_CONFIG_UBATCH_INDEX

  • Extended support for the hybrid memory mode from default (single GPU) to MGMN mode

  • Enabled support for combining the phases for cudssExecute() in a single call and added separate phases CUDSS_PHASE_REORDERING and CUDSS_PHASE_SYMBOLIC_FACTORIZATION for reordering and symbolic factorization

  • Enabled a new configuration parameter CUDSS_CONFIG_ND_NLEVELS which can control the nested dissection depth for reordering with CUDSS_ALG_DEFAULT

  • Enabled support for symmetric matrices in CUDSS_ALG_1 and CUDSS_ALG_2 reordering algorithms

  • Re-enabled passing a different matrix on the solve phase (was disabled in 0.5.0), with the restrictions specified in cudssExecute()

Breaking changes:

  • Disabled support for batched matrices in the MGMN mode

  • Changed the enum values for cudssPhase_t and the parameter type for phase in cudssExecute from cudssPhase_t to int

Important bug fixes:

  • Fixed a sporadic accuracy failure for non-symmetric matrices with CUDSS_ALG_1 or CUDSS_ALG_2 for reordering (CUDSS-732).

  • Fixed incorrect (perturbed) pivot scaling (CUDSS_ALG_1 for CUDSS_CONFIG_PIVOT_EPSILON_ALG) for symmetric matrices (CUDSS-706)

  • Fixed incorrect reordering result with CUDSS_ALG_DEFAULT for nested dissection depth large enough compared to the number of rows (CUDSS-873)

Known issues:

  • Default matching algorithm (same as CUDSS_ALG_5) produces incorrect results for hybrid execute and hybrid memory modes when the scaling vectors are non-constant (CUDSS-882). As a workaround, one can use CUDSS_ALG_4 or other values of matching algorithm other than the default and the last options (CUDSS-882).

  • In case the input matrix is distributed, if some processes have empty local parts of the matrix, an out-of-bounds device access can happen (CUDSS-913). As a workaround, one should make sure all processes have non-empty local parts (CUDSS-913).

cuDSS v0.5.0#

New Features:

  • Multi-Threaded (MT) mode with prebuilt standalone threading layer for GNU OpenMP on Linux and VCOMP (VCOMP140.dll) on Windows, as well as with custom user-defined threading backends

  • Multi-threaded reordering for CUDSS_ALG_DEFAULT reordering algorithm

  • Hybrid host/device execute mode to enable using the host on factorization and solve (improved performance for small matrices)

  • Improved performance and memory requirements for the hybrid memory mode

  • Blackwell GPU architecture support (sm_100, sm_120, sm_101)

Breaking changes:

  • Changed the function signature for cudssMatrixCreateBatchDn() and cudssMatrixGetBatchDn() to have an extra argument for the integer types of the arrays with scalar parameters of the batch (like nrows, ncols or ld)

  • Changed the definition of cudssMatrixFormat_t and cudssMatrixGetFormat() to make the matrix format enum values become bit flags (which can be combined) and added a flag CUDSS_MFORMAT_BATCH for querying whether a cudssMatrix_t is a batch

  • Dropped support for SLES 15.x for x <= 5 (upgraded minimal version of SLES to 15.6) and upgraded the minimal version of GLIBC supported to 2.28

Important bug fixes:

  • Fixed a bug when the internally symmetrized matrix pattern has number of nonzeros overflowing 32-bit integer maximum value (CUDSS-417).

  • Fixed a bug when the MGMN mode produced incorrect results for some of the larger matrices (CUDSS-601)

  • Fixed incorrect memory estimates returned for the hybrid memory mode (CUDSS-669)

cuDSS v0.4.0#

New Features:

  • Significant performance improvements for all reordering algorithms other than CUDSS_ALG_1 and CUDSS_ALG_2

  • Added support for non-uniform batching (solving multiple systems with different matrices and righthand sides) via new APIs like cudssMatrixCreateBatch<Dn|Csr>() and others similar to existing APIs for non-batch matrix objects and extending cudssExecute() to support batches

  • Added support for querying memory estimates via cudssDataGet() with CUDSS_DATA_MEMORY_ESTIMATES

  • Added installer support for Ubuntu 24.04

  • Added support for pip wheels on pypi.org and pypi.nvidia.com and for conda packaging

Breaking changes:

  • Added a new value CUDSS_DATA_MEMORY_ESTIMATES into the cudssDataParam_t enum

  • Starting with this release, cuDSS has a runtime dependency on cuBLAS (usually available as a part of CUDA Toolkit)

Important bug fixes:

  • Added CMake config version file and fixed CMake config for system-wide installation

Known issues:

  • For correct system-wide installation, cudss-config.cmake makes use of REAL_PATH which is only available since cmake 3.19 (which is newer than the default cmake version for Ubuntu 20.04, e.g.)

  • The MGMN mode of cuDSS with OpenMPI communication layer might run out of GPU memory due to a bug in OpenMPI/UCX. If you encounter this issue, consider setting export UCX_MEMTYPE_CACHE=n or export UCX_TLS=^cuda_ipc or switching to the NCCL communication backend as a workaround. These workarounds might lead to performance degradation. In such a case, please report it.

  • PIP wheels for Linux + x86_64 with version 0.4.0.2 might not work on some of older OSes due to a bug in patchelf 0.18.0. On affected systems, ldd libcudss.so.0 will return an error not a dynamic executable and using the shared library for linking with an application will produce an error ELF load command address/offset not properly aligned. The suggested workaround is to use the installation command pip install nvidia-cudss-cu12 which will install the patched wheels nvidia-cudss-cu12 0.4.0.2.post1.

cuDSS v0.3.0#

New Features:

  • Multi-GPU multi-node (MGMN) mode with prebuilt standalone communication layers for NCCL and OpenMPI, as well as with custom user-defined GPU-aware communication backends

  • Hybrid host/device memory mode which enables keeping the factor values in the host memory (RAM) and uses only a smaller device buffer as a temporary

  • Extended support to Linux ARM(aarch64) (Ubuntu 22.04, only on Orin (SM 8.7) devices)

Breaking changes:

  • Removed values CUDSS_STATUS_ARCH_MISMATCH and CUDSS_STATUS_ZERO_PIVOT from the enum cudssStatus_t as these values will not be used

  • Renamed the main header cuDSS.h as cudss.h to better align with other CUDA math libraries

Important bug fixes:

  • Fixed execution failures when multiple tiny matrices (less than 16x16) were solved re-using the same cudssData_t

  • Fixed incorrect result when factorization phase followed a re-factorization phase with CUDSS_ALG_1 and CUDSS_ALG_2 reordering algorithms

Known issue:

Error messages are seen during cuDSS installation on RPM-based systems (RHEL, Rocky, SLES)

failed to link /usr/lib/#INSTALL_TRIPLET#/libcudss_commlayer_nccl.so -> /etc/alternatives/libcudss_commlayer_nccl.so: No such file or directory
failed to link /usr/lib/#INSTALL_TRIPLET#/libcudss_commlayer_openmpi.so -> /etc/alternatives/libcudss_commlayer_openmpi.so: No such file or directory

The installation completes despite the failure to create a couple of symlinks for cuDSS.

To fix the issue, please apply the workaround ONLY after encountering the above issue. The issue and thus workaround is only applicable to RPM-based systems (RHEL, Rocky, SLES). The workaround will drop and recreate all symlinks intended for the cudss alternatives system.

update-alternatives --remove cudss /usr/lib64/libcudss/12/libcudss.so.0

/sbin/ldconfig

update-alternatives --install /usr/lib64/libcudss.so.0 cudss /usr/lib64/libcudss/12/libcudss.so.0 120 \
--slave /usr/lib64/libcudss.so libcudss.so /usr/lib64/libcudss/12/libcudss.so \
--slave /usr/lib64/libcudss_commlayer_nccl.so  libcudss_commlayer_nccl.so /usr/lib64/libcudss/12/libcudss_commlayer_nccl.so \
--slave /usr/lib64/libcudss_commlayer_openmpi.so  libcudss_commlayer_openmpi.so /usr/lib64/libcudss/12/libcudss_commlayer_openmpi.so \
--slave /usr/lib64/libcudss_static.a libcudss_static.a /usr/lib64/libcudss/12/libcudss_static.a \
--slave /usr/lib64/cmake/cudss cudss_cmake /usr/lib64/libcudss/12/cmake/cudss \
--slave /usr/include/cudss.h cudss.h /usr/include/libcudss/12/cudss.h \
--slave /usr/include/cudss_distributed_interface.h cudss_distributed_interface.h /usr/include/libcudss/12/cudss_distributed_interface.h

/sbin/ldconfig

After the steps are completed, confirm that all the symlinks exist. Expectation:

# ls -l /usr/lib64/cmake/cudss
... /usr/lib64/cmake/cudss -> /etc/alternatives/cudss_cmake

# ls -l /usr/include/cudss*
... /usr/include/cudss.h -> /etc/alternatives/cudss.h
... /usr/include/cudss_distributed_interface.h -> /etc/alternatives/cudss_distributed_interface.h

# ls -l /usr/lib64/*cudss*
... /usr/lib64/libcudss.so -> /etc/alternatives/libcudss.so
... /usr/lib64/libcudss.so.0 -> /etc/alternatives/cudss
... /usr/lib64/libcudss_commlayer_nccl.so -> /etc/alternatives/libcudss_commlayer_nccl.so
... /usr/lib64/libcudss_commlayer_openmpi.so -> /etc/alternatives/libcudss_commlayer_openmpi.so
... /usr/lib64/libcudss_static.a -> /etc/alternatives/libcudss_static.a

# ls -l /etc/alternatives/*cudss*
... /etc/alternatives/cudss -> /usr/lib64/libcudss/12/libcudss.so.0
... /etc/alternatives/cudss.h -> /usr/include/libcudss/12/cudss.h
... /etc/alternatives/cudss_cmake -> /usr/lib64/libcudss/12/cmake/cudss
... /etc/alternatives/cudss_distributed_interface.h -> /usr/include/libcudss/12/cudss_distributed_interface.h
... /etc/alternatives/libcudss.so -> /usr/lib64/libcudss/12/libcudss.so
... /etc/alternatives/libcudss_commlayer_nccl.so -> /usr/lib64/libcudss/12/libcudss_commlayer_nccl.so
... /etc/alternatives/libcudss_commlayer_openmpi.so -> /usr/lib64/libcudss/12/libcudss_commlayer_openmpi.so
... /etc/alternatives/libcudss_static.a -> /usr/lib64/libcudss/12/libcudss_static.a

cuDSS v0.2.1#

Important bug fixes:

  • Fixed host memory leaks

  • Fixed device memory bookkeeping which could cause read violation errors and segmentation faults when cuDSS is called repeatedly with the same cudssHandle_t and cudssData_t objects

  • Fixed incorrect results of iterative refinement for 1-based input matrices

  • Fixed incorrect internal temporary buffer size which could cause invalid memory accesses for small matrices

cuDSS v0.2.0#

New Features:

  • Performance improvements for non-symmetric and non-hermitian matrices for the reordering algorithm CUDSS_ALG_1

  • Support for user-defined device memory allocators/memory pools

  • Support for extracting permutations which account for both reordering and pivoting (via new values CUDSS_DATA_PERM_ROW and CUDSS_DATA_PERM_COL in the enum cudssDataParam_t) for reordering algorithms CUDSS_ALG_1 and CUDSS_ALG_2

  • Extended support to all SM architectures starting with Pascal (SM 5.0)

  • Extended support to Linux ARM(SBSA) (Ubuntu 20.04, Ubuntu 22.04, RHEL 8, RHEL 9, SLES 15)

Breaking changes:

  • Replaced value CUDSS_DATA_PERM_REORDER in the enum cudssDataParam_t with CUDSS_DATA_PERM_REORDER_ROW and CUDSS_DATA_PERM_REORDER_COL to separate row and column reordering permutations which can be different for non-symmetric reordering algorithm CUDSS_ALG_1

Important bug fixes:

  • Fixed incorrect solution for Hermitian matrices with non-disabled pivoting

  • Fixed sporadically incorrect solution on H100 due to shared memory allocation size

  • Fixed incorrect propagation of pivoting tolerance and epsilon from cudssConfig_t during cudssExecute()

  • Fixed sporadic hangs on GPUs with small number of SMs

cuDSS v0.1.0#

New Features:

  • Initial release

  • Support for single GPU, SM architectures: SM 7.0 and newer

  • Support Linux x86-64 (Ubuntu 20.04, Ubuntu 22.04, RHEL 8, RHEL 9, SLES 15)

  • Support Windows x86-64 (Windows 10, 11)

  • Support for single/double real/complex datatype for values and int datatype for indices

  • Synchronous API

Compatibility notes:

  • cuDSS requires CUDA 12.0 or above