News

v1.2 (released 2012-02-23)

Matrix Construction:
- Switched to template based coefficient functions (TCoeffFn and derived) and all depended classes, e.g. TDenseMBuilder, SVD and ACA low rank approximation.
- Rewrote HCA:
  - Simpler interface containing all neccessary functionality in single class.
  - Using template for value type.
  - Added base classes for permuted indices and for BEM applications using quadrature.
  - Added implementation for Laplace and Helmholtz also for linear ansatz spaces and with support for SSE2 and AVX.
- Cleaned up ACA implementation.
- Changed handling of recompression: should now be handled by default in low rank approximation algorithm and not by matrix construction class (to avoid recompression of optimal results).
Clustering Changes:
- Added TNDBSPPartStrat to be used in connection with nested dissection (trying various clusterings and choosing best for ND).
- Modified TNDBSPCTBuilder to more resemble algebraic version, e.g. average depth for interface clusters instead of maximal.
- Fixed bug in PCA based clustering and added version for cardinality based clustering.
- Added various flags to modify clustering, e.g. synchronisation of interface depth, enforcing block clusters with same depth of corresponding clusters, using symmetrised weights in algebraic clustering.
Input/Output and visualisation:
- Fixed bug in reading dense matrices.
- Changed order of dimension for coordinate IO using Matlab format: now ncoord × dimension (e.g. as also used by Sparse Matrix Collection).
- Added VTK visualisation for coordinates (with various options, e.g. marking clusters or index connectivity) and BEM grids.
- Added Output of Grids in HLIB format.
- Added coordinate IO in MatrixMarket format.
Changes in LAPACK wrapper:
- added LAPACK workspace queries for optimal workspace size instead of using predefined block size
- using xGESDD for large matrices
various bug fixes.

v1.1

v1.1.1 (released 2011-11-29)

Deactivated default coarsening during matrix construction.
Added special H² matrix builder with predefined cluster bases.

v1.1 (released 2011-11-28)

changes in BEM code:
- Added support for AVX.
- Performance speedups in SSE2 implementation of Helmholtz and Maxwell kernels.
- Runtime detection of SSE2/AVX availability and automatic choice of optimal kernel.
Added matrix_format function to matrix coefficient functions to define whether unsymmetric, symmetric or hermitian (default: unsymmetric).
Default build function in matrix builders now without format argument.
Added support for ILP64 BLAS/LAPACK implementations (64bit integers).
Added support for AMD-LibM (integrated in binary Linux distributions).
Added vector IO in MatrixMarket format.
Cleaned up C++ examples (thereby also removing Boost link dependency).
several bug fixes

v1.0

v1.0.1 (released 2011-09-28)

OpenMP exception handling changed: now all threads will stop as soon as possible in case of an error
fixed several, previously undetected, non-critical compiler warnings (MS Visual C++)
bug fixes

v1.0 (released 2011-07-01)

HLIBpro v1.0 is a major rewrite/reorganisation of many of the 𝓗-matrix algorithms.
The following list of changes only covers the main topics and is by far not complete.

added distributed computing via MPI for matrix construction and factorisation
added 𝓗²-matrices
added internal multi-level graph partitioning for blackbox clustering
added support for piecewise linear basis functions and Maxwell EFIE/MFIE
rewrote interface to BLAS/LAPACK
rewrote C interface with better mapping of internal C++ and C types
increased robustness of matrix factorisation in case of bad-conditioned matrices
increased speedup of matrix factorisation in multi-threaded computations
many performance improvements and bug fixes

v0.13

v0.13.6 (released 2009-01-30)

added optional diagonal scaling of 𝓗-matrices during LU factorisation
added blockwise accuracy, e.g. accuracy depending on current matrix block
rewrote accuracy handling in C bindings
simplified BSP partitioning methods and added regular cardinality based and principle component based clustering
added optional balancing of tree depth in cluster tree construction with predefined partitioning
implemented optional double precision computation of matrix inversion and low-rank truncation in single precision mode
fixed bug in calling single precision norm functions of LAPACK
fixed bug in PostScript output and modified 𝓗-matrix output in PostScript format
added support for Jacobi based SVD (sgejsv and dgejsv) in LAPACK v3.2

v0.13.5 (released 2008-09-23)

removed ID based cluster tree computations in matrices
always computing SCC in algebraic clustering, also in nested dissection clustering
reordering clusters depending on size ratio (large first)
fixed bug with filenames without directories
fixed non-exception safe OpenMP usage
added matrix reduction to nearfield part
added dense low-rank multiplication if result is large dense matrix

v0.13.4 (released 2008-04-24)

fixed solve functions in TLU, TLDL (checking for NULL blocks)
fixed OpenMP call with zero threads in TLU TLDL and TMatrixInv
fixed operator = in autoptr (wrong const)
removed unnecessary checks in TArray::copy
fixed recursive call in restrict_blockdiag
replaced fixed constants by type dependent constants in lapack.cc
fixed TMatrixInv::multiply_diag when only D is dense

v0.13.3 (released 2008-03-27)

fixed several warnings from Visual C++ and Intel C++ compilers
moved all global variables and functions into HLIB namespace (except xerbla override)
enabled user defined prefix for functions and types in C interface and added override for namespace name
reactivated cardinality check when using HLIB_BSP_AUTO

v0.13.2 (released 2008-02-29)

replaced threads and mutices by OpenMP (thread start only, no scheduling)
included log file support in addition to stdout
added parallel LDL^T factorisation (DD and blockdiag only)
added parallel blockdiag LU factorisation
added zero approximation during matrix construction (for nearfield only)
fixed bug in algebraic nested dissection clustering (wrong path length in interface)

v0.13.1 (released 2008-02-04)

reduced memory consumption/fragmentation in ACA generated matrices with large rank
added Fiduccia/Mattheyses bisection optimisation for BFS clustering
added FFT for vectors by implementing support for FFTW3 (optional)
fixed bug in TBSPPartCTBuilder when using more than two partitions
fixed potential issues in sorting algorithms
fixed type issues with *_bytesize functions in C interface
fixed bug in PostScript visualisation of matrices if matrix norm is zero
fixed issues with GCC-4.3
fixed bug in command line parsing of configuration system
minor modifications to SCons system to increase userfriendliness

v0.13(.0) (released 2007-12-19)

general Algorithmic Changes
- support for single precision arithmetic; has to be decided before compiling HLIBpro
- made complete C++ functions and classes visible from outside instead of just C interface functions
- rewrote complex arithmetic to distinguish between symmetric and hermitian matrices; added LDL^H and LL^H factorisations
- inversion now based on LU, thereby reducing memory consumption (roughly halved)
- added computation of the diagonal of the inverse without computing the inverse
- added evaluation of LU, LDL^T factorisations (instead of just solving)
- removed point-wise LU and LDL^T factorisation (only blocked) to improve robustness with zeroes on diagonal
- added (optional) check and fix for singular sub matrices during inversion and factorisation
- added complex valued HCA
- new version of ACA+
- multiplication C = ADB with diagonal D implemented
- implemented bilinear forms for Helmholtz single and double layer potential
- implemented bilinear form for acoustic scattering
- rewrote algebraic clustering for sparse matrices; added support for Scotch and CHACO
- added support for periodic coordinates in clustering
- added clustering with user defined index partition on first level in cluster tree
- added standard admissibility for algebraic clustering
- added maximal level in clustering to prevent infinite recursion
- modified solvers to handle complex valued data
- added permutation of dense matrices without temporary storage (needed in IO)
parallel Arithmetic
- added thread parallel algorithms for matrix construction, matrix multiplication, inversion and LU factorisation
- redesigned thread pool, thereby fixing race conditions
- added support for Windows threads
- fixed several issues with thread safety
Input and Output
- added general I/O functions with autodetection of file format
- added output of matrices in Harwell/Boeing format
- added MatrixMarket format
- added support for Ply and surface mesh format (NetGen) for Grid I/O
- fixed format errors in SAMG output
- conversion of arbitrary matrices to sparse format when writing in SAMG or Harwell/Boeing format
- fixed support for symmetric matrices in Harwell/Boeing format
C interface
- prefixed all functions, types and constants with hlib_ (or HLIB_) to prevent collisions with other definitions (OS or libraries)
- added support for C99 complex types (if available)
- added hlib_set_coarsening to activate/deactivate coarsening during matrix construction (default: on) and matrix arithmetic (default: off)
- added hlib_matrix_inv_diag to return diagonal of inverse
- added hlib_matrix_is_complex to test for real or complex valued matrices
- added hlib_set_nthreads to set number of threads
- added hlib_coord_t as special type for coordinates
- separated stop criterion and solver in solver interface
Miscellaneous
- updated CPUflags and Rmalloc
- fixed optimisation issues (leading to infinite loops) in enclosed CLAPACK

v0.12 (released 2006-11-01)

Algorithmic Changes
- added (blocked) LDL^T factorisation (now default for symmetric matrices)
- no longer need extra matrix in matrix inversion
- using ACAFull in HCA (instead of SVD)
- adaptively choosing quadrature and interpolation order in ACA and HCA
- rewrote matrix addition to support general cases, e.g. low-rank to blocked
- rewrote low-rank truncation handling
- support for METIS in algebraic clustering routines
- added basic support for "dense" sparse matrices, e.g. with highly coupled indices
- added SSE2 based HCA algorithm
- added infinity norm for vectors
- using norm of preconditioned residual for all solvers if preconditioner is present
- added MINRES iteration
- using ADM_AUTO as default admissibility
- finally removed all asserts and replaced by internal error checking
Input and Output
- VRML97 support
- added Matlab compression (Matlab v7) and structs support
- support for Harwell-Boeing matrix format (read-only)
- modified PostScript output of block-wise SVD; now scaled w.r.t. 2-norm of matrix
OS and Library support
- MS Windows support
- shared libraries for Linux and Windows
- changed configure system to better handle MS Windows environment
- added internal xerbla to handle LAPACK errors directly
C interface
- automatic choice of matrix building in hlib_matrix_build_bem_grid
- introduced vector_t as type to vectors (no more C arrays)
- added Gauss and Sauter triangle quadrature rules
- added functions to access matrix and vector entries
- added copyto and copyto_eps functions
- added hlib_matrix_build_dense to build 𝓗-matrix from dense matrix
- changed solver management
Miscellaneous
- several improvements and bug fixes
- cleaned up error codes
- updated CPUflags and Rmalloc

v0.11 (released 2006-05-29)

Arithmetic
- added ACA-Full
- added HCA (hybrid cross approximation)
- complex valued ACA and SVD
- added copy with coarsening for 𝓗-matrices
- added computation of spectral norm for the inverse of a matrix
- support for permutations in matrix-vector multiplication of sparse matrices
- added support for Laplace SLP/DLP and 3D triangle surface grids
- fixed issues with degenerated bounding boxes in geometrical clustering
Input/Output
- support for PLTMG matrix format
Miscellaneous
- replaced error handling with exceptions
- added modified CLAPACK as default implementation of LAPACK to HLIBpro
- integrated CPUFlags into configure system
- added function for fast reciprocal square root

v0.10 (released 2006-04-05)

Arithmetic
- initial support for complex arithmetic
- support for symmetric matrices in arithmetic
- implemented block LU factorisation
- implemented LDL^T factorisation
- added Frobenius norm for sparse matrices
- support for CRS format in sparse matrices
- added Jacobi and SOR matrix types (for matrix-vector multiplication)
- implemented hierarchical domain decomposition with parallel arithmetics
Parallel Algorithms
- thread-parallel Cholesky factorisation
- thread-parallel coarsening of 𝓗-matrices
- fixed thread-parallel LU and inversion
- fixed dead-locks in thread-pool
- added direct communication in BSP mode
- parallel addition of matrices and vectors via streams
Input/Output
- support for Matlab and SAMG format
Miscellaneous
- introduced C interface functions and types
- added configure system for Makefiles
- added progress meter support for arithmetic
- added internal RTTI system
- support for memory consumption query on HP-UX
- rewrote error handling

v0.9 (released 2004-11-30)

first public version as PHI (Parallel H-matrix Implementation)
merged BSP-parallel and thread-parallel versions of 𝓗-matrix library