Table of Contents

7. Release Notes VfsTools

Table of Contents

7.1 Bug fixes

• The SysMatrix Lanczos eigensolver has had a few bug fixes related challenging vibration spectra. (4.5.4: June 11, 2021)

• The SysMatrix module out-of-core direct sparse solver was non-functional. (4.4.6: May 3, 2019)

• The SysMatrix module eigensolution needed 64 bit integer logic for large eigenvalue systems. (4.4.3: July 19, 2017)

• The SysMatrix module eigensolution strategy when using the iterative linear equation solver was not properly disabling automatic shifting. (4.2.2: June 26, 2017)

• The SysMatrix module did not properly order eigenvectors in some cases using the Lanczos eigensolver. (4.2.0: September 19, 2012)

7.2 New features and changes

• The iterative solver preconditioner has been improved for hex dominated grids. (4.5.4: June 11, 2021)

• The initial shift used when finding lowest vibration modes is now calculated using Gershgorin circles. (4.5.4: June 11, 2021)

• The AMLS eigensolver has had significant performance improvements with respect to the variation of the SYSMATRIX_AMLS_CUTFACT1 and SYSMATRIX_AMLS_CUTFACT2 factors. (4.5.4: June 11, 2021)

• The SysMatrix module parameters SYSMATRIX_AMLS_CUTFACT1 and SYSMATRIX_AMLS_CUTFACT2 have been added to control AMLS accuracy. (4.5.1: September 23, 2020)

• The IPardiso module has been added to emulate the interface to the Intel MKL PARDISO direct sparse solver. (4.5.1: July 29, 2020)

• The DofTab module now supports a block id to group elements for parallel assembly into application specific groups. Set the current block id using vfs_DofTabSetAssemBlock. (4.5.1: July 29, 2020)

• The SysMatrix module iterative solver now supports Hermitian matrices. (4.5.1: May 29, 2020)

• The SysMatrix module direct solver now supports Hermitian, fully complex symmetric and fully complex symmetric structure with non-symmetric coefficients. (4.5.1: May 29, 2020)

• The SysMatrix module default eigensolution type for vibration is now SYS_EIGEN_LANCZOS. The eigensolution type for buckling is always subspace. (4.5.1: May 22, 2020)

• The DofTab module functions vfs_DofTabThreadAssemNum and vfs_DofTabThreadAssemGroups and the SysMatrix module functions vfs_SysMatrixSetNumThreadsAssem, vfs_SysMatrixThreadAssem, vfs_SysMatrixThreadAssemFull and vfs_SysMatrixThreadAssemDiag. have been added to implement threaded element assembly. (4.5.0: August 21, 2019)

• The SysMatrix module function vfs_SysMatrixSetInitSol has been added to allow specification of an initial guess for the iterative solver. (4.5.0: August 19, 2019)

• The SysMatrix module has been significantly enhanced with a new multifrontal, in-core and out-of-core direct sparse solver and AMLS (Automatic Multi-Level Substructuring) eigensolver. All solvers have been fully parallelized using C++ threading and OpenMP and feature extensive use of the BLAS. (4.5.0: August 15, 2019)

• The SysMatrix module iterative solver has been parallelized for portions of the iteration process using OpenMP. (4.4.5: October 19, 2018)

• The SysMatrix module block Lanczos eigensolver has been significantly enhanced. An automatic shifting strategy is now available to move efficiently through frequency ranges for the extraction of large numbers of vibration modes for large scale problems. (4.4.4: April 10, 2018)

• The DofTab and SysMatrix modules now support the computation of rigid body modes very efficiently. (4.4.3.r1: September 13, 2017)

• The SysMatrix module now supports the Intel Pardiso and MUMPS direct sparse solvers. These solvers may be used in lieu of the native sparse solver implementation. (4.4.3 August 3, 2017)

• The SysMatrix module parameters for out of core factor control have been changed. Enable out of core factor storage using vfs_SysMatrixSetParami with parameter SYSMATRIX_FACTOR_OOC. Set the out of core factor file name using vfs_SysMatrixSetOocFile with parameter SYSMATRIX_FACTOR_FILE. (4.4.3 July 20, 2017)

• The SysMatrix module now supports out of core eigenvector storage. Enable out of core eigenvector storage using vfs_SysMatrixSetParami with parameter SYSMATRIX_EIGEN_OOC. Set the out of core eigenvector file name using vfs_SysMatrixSetOocFile with parameter SYSMATRIX_EIGEN_FILE. (4.4.3 July 20, 2017)

• The SysMatrix module iterative solver preconditioner has been substantially improved for models dominated by linear elements. (4.4.2 February 6, 2017)

• The SysMatrix module now supports iterative solver preconditioning for nonsymmetric matrices using GMRES. (4.4.2 February 6, 2017)

• The SysMatrix module has optimized the degree of freedom ordering for the iterative solver preconditioner. (4.4.1 June 21, 2016)

• The SysMatrix module now supports an automatic shifting strategy for vibration mode extraction. This strategy is now the default. (4.4.1 April 19, 2016)

• The SysMatrix module now supports coarse grained parallelization of vfs_SysMatrixSolveMult and vfs_SysMatrixReduce. (4.3.6: October 9, 2015)

• The DofTab and SysMatrix modules functions vfs_DofTabSetNumThreads and vfs_SysMatrixSetNumThreads have been added to support coarse grained shared memory parallelization for system degree of freedom reordering, matrix reduction and eigensolution. The underlying direct sparse solver is currently only fine grained parallelized within the BLAS routines. (4.3.1: March 17, 2014)

• The SysMatrix module function vfs_SysMatrixReduce has been significantly optimized for performance. (4.3.0: March 17, 2014)

7.3 Existing Application Programming Interface Changes

• The SysMatrix module function vfs_SysMatrixSetMPC has been removed. The MPC equations are now set in the DofTab module using vfs_DofTabSetMPC. The SysMatrix module function vfs_SysMatrixPreAssem has been removed. It is now unnecessary to pre assemble the element degrees of freedom in SysMatrix, this information is accessed from the DofTab object which must now be set in the SysMatrix object using vfs_SysMatrixSetObject. (4.5.0: August 15, 2019)

7.4 Known problems and limitations