Version 4.0.0, FUTURE, 2020 (this list is tentative):

    * GrB_wait(), with no inputs: will be removed
    * GrB_wait(&object): polymorphic function will be added
    * GrB_*_nvals: will no longer guarantee completion; use GrB_wait(&object)
        or non-polymorphic GrB_*_wait (&object) instead
    * GrB_error: will have two inputs: a string (char **) and an object

Version 3.3.3, July 14, 2020

    * (20) bug fix: w<mask>=A*u with mask non-empty and u empty (issue #13).
        affects mxm (A*B when B is a vector), vxm, and mxv.
    * GraphBLAS v3.3.3 released as part of SuiteSparse v5.8.1

Version 3.3.2, July 3, 2020

    * minor changes to build system
    * GraphBLAS v3.3.2 released as part of SuiteSparse v5.8.0

Version 3.3.1, June 30, 2020

    * (19) bug fix: incorrect typecasting when GrB_assign or GxB_subassign
        is simple: C=A where A is sparse or dense, in GB_dense_subassign_24.
        Bug introduced in v3.2.0.
    * revised gbmake: to allow GraphBLAS to be compiled in Octave

Version 3.3.0, June 26, 2020

    * GrB_wait( ): with no input arguments, has been deprecated.  It will
        be removed in V4.0.
    * added complex types: GxB_FC32 and GxB_FC64, many unary operators,
        binary operators, monoids, and semirings
    * added GrB_*_apply_BinaryOp1st and 2nd: also GxB version with GxB_Scalar
    * added bitwise operators: and their monoids and semirings
    * added predefined GrB* monoids and semirings: from the v1.3 spec.
    * MATLAB interface: added complex matrices and operators, bitwise
        operators; improved performance
    * changed typecasting rules: for casting floating point types to integers
    * added GrB_*_wait: wait for specific object to complete
    * added GrB_*_resize: same as prior GxB_*_resize functions
    * added GrB_kronecker: same as prior GxB_kron
    * added version methods: GrB_getVersion, GRB_VERSION, GRB_SUBVERSION
    * added GrB_*_removeElement
    * (18) bug fix: fixed typecasting in GB_dense_subassign_23, generic case
    * (17) bug fix: non-polymorphic GrB_eWiseAdd and eWiseMult functions
        were misnamed.
    * DRAFT interfaces: A few functions have been added to use CUDA and the
        Intel MKL library.  These are visible in GraphBLAS.h but are
        undocumented; do *not* use them yet.  They will likely change without
        warning, and without changing the SuiteSparse:GraphBLAS version number.

Version 3.2.2, Apr 2, 2020

    * (16) bug fix to MATLAB interface: for matrices with dimension > 2^53.
        Note that MATLAB will not display the size correctly in 'whos', which
        rounds the int64 values of m and n for [m,n]=size(A) of a GrB_matrix to
        a 'flint', which is a double value, that then gets rounded.  This is
        outside of my control.  size(A) is correct, just the 'whos' is wrong.
    * port to Microsoft Visual Studio: including GraphBLAS/Demo and
        GraphBLAS/Test, which had not been ported in v3.1.2.
    * remove dependency on m4: end-users no longer need m4;  still needed by
        the Source/codegen*.m scripts but those are for development only.

Version 3.2.1, Mar 10, 2020

    * GAP benchmarks in MATLAB: in GraphBLAS/GraphBLAS/GAP (all but CC).
    * atomic read/write: faster atomics for icc (see Source/GB_atomics.h)
    * install name for Mac: in alternative/Makefile and Tcov/Makefile
    * enable -DGBCOMPACT from CMake: for faster Travis builds
    * MATLAB interface: better error message in GrB.reduce
    * MATLAB triangle count: added sorting heuristic in GrB.tricount.
    * bug fix for GraphBLAS/Demo/simple_timer: better selection of which
        timer to use; simple_timer.[ch] made consistent.
    * no bug fixes needed in primary GraphBLAS library: just in Demo, test,
        and alternative/Makefile.

Version 3.2.0, Feb 20, 2020

    * GxB_*_define for user-defined compile-time objects: removed.  Not
        compatible with the faster kernels for mxm and dense matrices/vectors.
        Use the GrB_*_new functions in the GraphBLAS C API Specification
        instead.
    * faster saxpy-based matrix multiply (about 5x to 10x for mxv and vxm):
        removed Sauna workspace.  Heap method removed.  Hash method added.
    * better performance for dense matrix and vectors: NOTE: see bug (19) above
    * faster typecast of the mask matrix M: GB_mcast replaces cast_M
    * added GB_BURBLE: for development diagnostics
    * changed default chunk size: from 4K to 64K
    * added the PAIR binary operator: f(x,y)=1
    * added the ANY binary operator: f(x,y)=x, or f(x,y)=y ; arbitrary choice
    * added structural mask: from v1.3 C API Specification
    * added GrB_DESC_*: predefined descriptor, from v1.3 C API Specification
    * many atomics added: for the faster matrix multiply.  These changes have
        not been ported to Microsoft Visual Studio, which only supports a
        subset of "#pragma omp atomic" statements.  This will be resolved in a
        future version; in the meantime, use v3.1.2 with MS Visual Studio
        instead of v3.2.0.
    * no bug fixes

Version 3.1.2, Dec 16, 2019

    * (15) bug fix in parallel matrix-matrix multiply: could occur when # of
        threads is larger than the # of columns of B, for C=A*B, and when
        B is a standard matrix with one or more empty vectors.
    * (14) bug fix for MATLAB interface: A(58) and A(:) were conflated.
    * compiler port: changes to allow GraphBLAS to be compiled with older
        compilers (pre ANSI C11), and Microsoft Visual Studio.

Version 3.1.1, Oct 21, 2019

    * minor edits: user guide and comments in code

Version 3.1.0, Oct 2, 2019

    * added MATLAB interface: GraphBLAS/GraphBLAS is new.  In Source/, added
        global pointer to printf for MATLAB mexPrintf, pointer to
        mexMakeMemoryPersistent for Sauna workspace.  Changed how GraphBLAS
        objects are printed with GxB_print.  Changed how duplicate indices are
        handled in assign and extract, to match the MATLAB stadard.  Added
        helper functions for MATLAB (GB_matlab_helper.[ch]).
        Code size: @GrB is 9.7KLOC, test/ is 4.5KLOC).
    * bug counter added to this ChangeLog: to count # of bugs that appeared
        in formal releases that affect production code.  The count excludes
        bug fixes for test code, bugs in the demo codes, bugs introduced
        in beta versions that were fixed before any formal release, and
        bugs prior to version 1.0.  Code size of Source/, Include/ excluding
        Source/Generated, and Config/*.m4, is 42,659 lines (not including the
        new MATLAB interface).  13 bugs / 42K lines is a bug rate of 0.3 bugs
        per KLOC, much lower than most commercial software, but higher than
        UMFPACK, CHOLMOD, etc (with about 0.1 bug per KLOC).  GraphBLAS is a
        much more complex library, from the external view, than solving Ax=b.
        If UMFPACK has a bug, then Ax-b is typically large; there is no
        'residual' to check for GraphBLAS.  Also, in GraphBLAS, the test suite
        has about the same size as the main library (32K lines in Test/ and
        Tcov/).  For UMFPACK, etc, the test suite is always about 1/3 the size
        of the library itself.
    * 'make dox': for doxygen removed (not really that useful)
    * (13) bug fix to GB_reduce_to_vector: to avoid integer divide-by-zero for
        a matrix with n=0 columns.
    * (12) bug fix to GB_accum_mask: when C+=T if C has no entries except
        pending tuples
    * (11) bug fix to GB_resize: when pending tuples exist and vdim is growing
        from vdim <= 1 to vdim > 1, matrix must be finished first.
    * (10) bug fix to GB_subref_phase1: "int nI" parameter should be int64_t.

Version 3.0.1, July 26, 2019

    * version number: Three changes to the user-visible API are not
        backward-compatible with V2.x: the added parameters to GxB_init and
        GxB_SelectOp_new, and the change in the type of the Thunk argument for
        GxB_select.  Thus, the SO version of SuiteSparse:GraphBLAS is now 3, no
        longer 2.  This change only affects SuiteSparse:GraphBLAS GxB_*
        extenstions, not any GrB_* functions or definitions.
    * added GxB_Scalar: acts like a GrB_Vector of length 1.
    * OpenMP parallelism: added nthreads and chunk parameters to GxB_set/get.
    * added parameter to GxB_init: bool user_malloc_is_thread_safe,
        for the MATLAB mexFunction interface, or any other malloc library that
        might not be thread-safe.  mxMalloc is not thread-safe.
        This change is not backward compatible with Version 2.x.
    * changed thunk parameter of GxB_select:  was (void *), now GxB_Scalar.
        This change is not backward compatible with Version 2.x.
    * added parameter to GxB_SelectOp_new: to specify the type of the Thunk.
        This change is not backward compatible with Version 2.x.
    * added options to GxB_get: determine if a matrix is hypersparse or not,
        global library, API information, nthreads, and chunk.
    * added options to GxB_set: nthreads, and chunk.
    * new operators and semirings: RDIV (f(x,y)=y/x) and RMINUS (y-x)
        binary operators.

Version 2.3.5, Oct 20, 2019

    * minor update: fix for tests in MATLAB R2019b

Version 2.3.4, July 4, 2019

    * Collected Algorithm of the ACM
    * (9) minor bug fix to GrB_*_extractTuples: nvals was left unchanged
        if the matrix or vector had no entries (now returned as zero).

Version 2.3.3, May 27, 2019

    * minor changes to the documentation: no change to the code

Version 2.3.2, Mar 18, 2019

    * GxB_Matrix_Option_set: removed spurious check of input matrix

Version 2.3.1, Mar 9, 2019

    * _Generic:  further modifications for 'int' vs 'const int', needed for
        icc 19.0.0.
    * (8) bug fix in user_def1.m4: compile-time GxB_Semring_define with
        terminal monoids

Version 2.3.0, Feb 25, 2019

    * early exit: for integer TIMES monoids (terminal value is 0);
        cannot use zero for floating-point, to preserve NaN behavior
    * GrB_assign / GxB_subassign: further exploit of aliased inputs
    * Test/: MATLAB mexFunctions now link against the dynamic -lgraphblas
    * bug fix for Demo/mis*: random number generator could create
        duplicate scores, which leads to a stall
    * terminal values for user monoids: added GxB_Monoid_terminal_new,
        GxB_Monoid_terminal_define, and GxB_Monoid_terminal
    * added GxB_init: GrB_init with malloc/calloc/realloc/free redefinition
    * _Generic: compilers differ on _Generic(x,int:,const int:). gcc, clang,
        icc 18.0.0 treat int and const int the same; icc 18.0.3 treats them
        as different.  This is a result of an ambiguity in the ANSI C11
        specification.  Minor update so that the use of _Generic(...) is
        compatible with all compilers.
    * early exit: for GrB_reduce

Version 2.3.0 (BETA1), Feb 16, 2019

    * simplified GBI_*_iterators
    * towards OpenMP: PARALLEL comments added to most files (all upper case)
        where parallelism will be added in the future.
    * early exit: for monoids: MIN, MAX, AND, OR, based on terminal values
    * Demo/bfs*: much faster (prior versions had performance bug)
    * GrB_assign for accum/mask step: faster, zombies and pending tuples
        exploited by C<M>=accum(C,T) for any GraphBLAS method, when either the
        mask M or accum are present.
    * moved persistent thread-workspace from the matrix to a global array
    * added isequal function to Demos/
    * added import/export method
    * added nthreads: to descriptor, the matrix, and a global nthreads
        setting, and added Context as parameter in many internal
        functions, to pass in Context->nthreads for future parallelism
    * defined all enum constants explicitly: no change to their values,
        this just ensures they remain fixed in future versions

Version 2.2.3, Dec 30, 2018

    * added doxygen documentation: minor changes to the code
        comments to accomodate doxygen.  Added Doxyfile settings file.

Version 2.2.2, Dec 18, 2018

    * GxB_print: better output for compile-time user objects
    * (7) bug fix: for GxB_Type_define, for GrB_*_build.
    * (6) bug fix: for GxB_Semiring_define, which was unable to access
        the predefined GxB_*_BOOL_MONOIDs.

Version 2.2.0, Nov 29, 2018

    * identical to 2.2.0 (BETA4): date changed, and "BETA4" removed.
        Demo/choldemo removed (testing artifact, not needed).

Version 2.2.0 (BETA4), Nov 28, 2018

    * minor change to GxB_get, GxB_set (all functions using va_arg):
        const removed from parameter definitions to silence spurious warnings
        from clang version 10.0.0, Mac OSX 10.14.
    * added Doc/CONTRIBUTOR-LICENSE.txt
    * added Doc/README_Doc.txt: includes instructions for OpenMP on the Mac
    * minor changes to comments of GB_subref_template: to match the ACM TOMS
        paper discussion of GrB_extract
    * included the GraphBLAS Extras: triangle counting, k-truss, and
        Kronecker matrix generator
    * minor changes for gcc -Wall -Wpedantic -Wextra, and icc -w3: to fix or
        silence warnings.  In a few cases, prior versions were relying on
        extensions to the ANSI C11 standard in gcc, clang, xlc.  The extensions
        are widely supported but best avoided anway.

Version 2.2.0 (BETA3), Nov 23, 2018

    * removed persistent thread-local O(n) workspace:  the Mark,
        Flag, and Work arrays in GB_thread_local in prior versions are removed.
        Replaced with temporary workspace, except for C=A*B using Gustavson's
        method, which now uses the C->Sauna workspace, held in the output
        matrix.
    * better support for user-application threads: GrB_finalize is now fully
        compliant with the spec.  User applications can use POSIX or OpenMP
        threads, or no threading, and use GraphBLAS in a thread-safe manner.
        Added OpenMP and POSIX pthread demos.
    * bug fix: freeing an object (monoid, matrix, or vector) that is
        dependent on another user-defined objects (an operator or type) that
        has already been freed led to the reading of an invalid value: the size
        of the object.  This only affects the memory usage statistics for
        testing only, not production use.
    * beta bug fix: memory leak in pagerank_demo program (bug first appears in
        2.2.0BETA2, not in any non-BETA final release

Version 2.2.0 (BETA2), Nov 15, 2018

    * added additional pagerank example in Demo/
    * beta bug fix: GxB_Monoid_define: bug fix for C struct types.  bug first
        appears in Version 2.2.0 (BETA1), not in any non-BETA final release. 

Version 2.2.0 (BETA1), Nov 2, 2018

    * added GxB_*_define: to create user-defined objects at compile-time.
        All internal macros renamed to add the GB_ prefix, to help avoid
        name conflict with possible user-defined objects and macros.
    * changed default format to GxB_BY_ROW
    * performance improvements to GrB*assign* and GrB*extract
    * added PageRank demos
    * added GxB_*print: to display all GraphBLAS objects

Version 2.1.0, Oct 14, 2018

    * identical to V2.1.0 BETA2: except for a minor update to the user guide,
        and date of release

Version 2.1.0 (BETA2), Sept 17, 2018

    * user function z=f(x,y): passed to GrB_BinaryOp_new, may now be called as
        z=f(z,y), with x and z aliased.  This is permitted by the API
        specification, and greatly improves performance of user-defined
        semirings.

Version 2.1.0 (BETA1), Sept 11, 2018

    * major update: added hypersparse and CSR formats, colon notation, and
        user selection of the method used by C=A*B.  All changes to the API are
        backward compatible with Version 2.0, so the SO version does not
        increase (it is still 2.x).
    * added GxB_AxB_METHOD: for user selection of C=A*B method
    * added GxB_RANGE, GxB_STRIDE and GxB_BACKWARDS: for MATLAB-like colon
        notation: begin:end and begin:inc:end.
    * added GxB_*Option* functions: to control hypersparsity and CSR/CSC format
    * added GxB_set and GxB_set: to set/get the descriptor and other options
    * (5) bug fix: if the accum operator z=f(x,y) was user-defined with
        different built-in types for x, y, z, the typecasting was wrong
    * GXB_* macros renamed GxB_*: old ones kept for backward compatibility

Version 2.0.3: July 4, 2018

    * (4) bug fix to GxB_resize
    * improvements to CMake script: version now defined only in CMakeLists.txt,
        and then cmake configures Include/GraphBLAS.h, README, and User Guide
    * bfs5 demo: asymptotically faster using sparse vector v but somewhat
        slower if entire graph is traversed

Version 2.0.2: June 25, 2018

    * added -lm to library dependency
    * minor changes to demos and user guide
    * removed unused code from Generated/* semiring functions

Version 2.0.1: Mar 15, 2018

    * (3) bug fix in GxB_kron: computed C incorrectly when A and B had pending
        updates on input

Version 2.0.0: Mar 12, 2018

    * moved opaque object definitions from Include/GraphBLAS.h to Source/GB.h
    * modifications to meet changes in the Nov 14, 2017, API specification:
        GrB_Monoid_TYPE_new changed to GrB_Monoid_new_TYPE.
        GrB_Type_new modified: 2nd argument no longer a type, but sizeof(type).
        This change is not backward compatible with Version 1.x, so this
        required an increase in the SO version, so the version number increased
        from 1.x to 2.x.
    * to allow non-C applications to access all GraphBLAS functions:
        These were just macros, now defined as both macros and functions:
        GrB_Type_new, GrB_UnaryOp_new, GrB_BinaryOp_new, and GxB_SelectOp_new.
    * added GxB_kron, GxB_resize (GxB_Matrix_resize and GxB_Vector_resize)
    * (2) bug fix to mask:  GrB_anymethod (C, C, ... , r_desc) where r_desc.outp
        is 'replace', and C is aliased to the Mask, was incorrect.

Version 1.1.2: Dec 28, 2017

    * build issues with cmake
    * performance improvement of dot product method, C=A'*B and v=u'*A,
        particularly when A, B and u have dense columns, or nearly dense
        columns.

Version 1.1.1: Dec 17, 2017

    * (1) bug fix to GrB_assign and GxB_subassign: result was incorrect when
        output C was the same as the input A or Mask.
    * performance improvement in C<M>=A*B and GrB_reduce to scalar
    * split AxB built-in semirings into Source/Generated/* for
        faster compilation
    * added memory usage statistics

Version 1.1.0: Dec 1, 2017

    * add new feature: GxB_SelectOp operator and GxB_select operation
    * to clarify which features of SuiteSparse:GraphBLAS are extensions to
        the spec, the names of functions and objects not in the spec have
        changed.  They are now GxB_* (GXB_ for macros).
    * modified how the global matrix queue is accessed, for thread safety
        in case the user application is multi-threaded

Version 1.0.0: Nov 25, 2017

    * transition to CMake
    * tested on many compilers (gcc 4.9 to 7.2 on Linux, clang 8 and gcc 6.2.0
        on the Mac, xlc 13.01 on IBM Power)
    * changed printf formats in Demo/ to silence warnings from older compilers
    * complex.h in gcc-6.2.0 on the Mac doesn't #define CMPLX;
        added to usercomplex.h
    * mergesort removed, quicksort performance improved
    * performance improvement for masked matrix-matrix multiply
    * bug fix for masked matrix-matrix multiply. In 0.5.0 only the Mask
        structure was used, not the values.  The spec requires the values of
        the Mask.  This is a bug but into only affects masked matrix multiply
        when the Mask has explicit zero entries.

Version 0.5.0: Nov 13, 2017

    * resolved icc -O3 segfault: Intel compiler bug fixed icc version 18.0
    * added triangle-counting demo in C (Demo/tricount.c) and MATLAB
        (Test/tricount.m).  See also Test/test69, Test/test70. and Test/test71.
    * performance enhancements to GrB_eWiseMult, GrB_assign, GrB_subassign,
        GrB_extract, and GrB_mxm, reducing time and memory.  mxm now exploits
        the mask during computation, to save memory and often saving time.
        This is essential for good performance for triangle counting.
    * reduced Test/testall.m and Tcov/testcov.m testing time from 2 hours to
        15 minutes, maintained 100% test coverage

Version 0.4.0: Oct 24, 2017

    * SPEC: SuiteSparse:GraphBLAS 0.4.0 fully conforms to 1.1.0 of the spec
    * GrB_assign functions added; all now conform to the 1.1.0 spec 
    * renamed all prior GrB_*_assign functions to GrB_*_subassign

Version 0.3.0: Oct 14, 2017

    * changes for spec 1.1.0
    * performance improvement of GrB_mxm, GrB_mxv, transpose, GrB_reduce;
        added workspace kept internally, reused for subsequent calls to
        GraphBLAS
    * performance improvement of bfs in Demo (v held as dense vector)
    * performance improvement of GrB_assign when A is a scalar
    * performance improvement of C<M>= ... mask operation
    * GrB_Column_extract and GrB_Column_assign renamed GrB_Col_*
        to match changes in the spec
    * changed GrB_*_setElement and GrB_*_extractTuples to match the spec
    * added GrB_INSUFFICIENT_SPACE error code for GrB_*_extractTuples
    * added GrB_INVALID_HANDLE
    * GrB_assign still does not match the spec (in progress).
        It differs on how it treats entries outside C(I,J), and it differs
        in the size and interpretation of the Mask.

Version 0.2.0: Sept 5, 2017

    * No significant change to the code; but preparing for wider release
    * content of GrB_stddef.h moved into Include/GraphBLAS.h and file removed
    * User Guide updated (SPEC discussion)
    * GraphBLAS.h modified (SPEC discussions)
    * Licensed under Apache 2.0; versions 0.1.x were limited releases
    * removed wathen_mod.m (to see it do 'type private/wathen' in MATLAB)

Version 0.1.2: Aug 30, 2017

    * added (double) to fpclassify in CAST macro, to silence
        spurious errors in gcc
    * minor typos
    * icc -O3 causes a segfault when compiling GB_AxB_builtin.c, so
        Lib/GraphBLAS_config.mk now uses -O2 with icc.
    * some versions of gcc have trouble finding libgraphblas.so.0
        when compiling the Demo (if GraphBLAS is not installed with
        'make install').  Instead of requiring a 'make install'
        static linking is now used for the Demo programs.  This
        has no effect on the GraphBLAS library itself.
    * changes for GraphBLAS spec 1.0.2 (Aug 10, 2017 version):
        * GrB_Vector_reduce_Monoid renamed to GrB_Matrix_reduce_Monoid
        * GrB_Vector_reduce_BinaryOp renamed to GrB_Matrix_reduce_BinaryOp
        * GrB_Row_extract was renamed in the spec to GrB_Col_extract, but 
            this version keeps the name GrB_Column_extract since it parallels
            the name GrB_Column_assign.

Version 0.1.1: Aug 28, 2017

    * minor changes to Makefiles and GraphBLAS_config.mk
    * port to Linux with gcc 4.9.3, 5.40, and 6.3.0
    * minor code changes to silence spurious gcc warnings;
        (&Ax[i]) changed to (Ax +(i)).
    * bug fix to GB_assign1.c (apply_pending_updates variable)

Version 0.1.0: July 31, 2017

    * first version released; only to GraphBLAS API Committee

