v4.0.1 (Jan 4, 2021)

Version 4.0.1, Jan 4, 2021

* substantial performance gains: compared with v3.3.3: up to 5x faster in
    BFS (with LAGraph_bfs_parent2), 2x faster in Betweeness-Centrality (in
    LAgraph_bc_bactch5); BC now faster than GAP for kron, urand, and
    twitter (the 3 largest matrices in the GAP benchmark).
* GrB_wait(), with no inputs: removed
* GrB_wait(&object): polymorphic function added
* GrB_*_nvals: no longer guarantees completion; use GrB_wait for that
* GrB_error: now has two parameters: a string (char **) and an object
* GrB_Matrix_reduce_BinaryOp: limited to certain built-in ops
* GrB_*_extractTuples: may return indices out of order
* removed internal features: GBI iterator, slice and hyperslice matrices
* bitmap/full matrices and vectors added: faster and lower memory usage
    when many entries present in a matrix or vector
* GxB_SPARSITY_CONTROL, GxB_SPARSITY_STATUS added: for matrix get/set
* positional operators and semirings: GxB_FIRSTI_INT32 and related ops
* jumbled matrices: sort left pending, like zombies and pending tuples
* GxB_get/set: added GxB_SPARSITY_* (hyper, sparse, bitmap, or full)
* GxB_HYPER: enum renamed to GxB_HYPER_SWITCH
* GxB_BITMAP_SWITCH added: for matrix/vector get/set and global get/set
* GxB*import/export: API modified
* GxB_SelectOp: nrows and ncols removed from function signature
* OpenMP tasking removed from mergesort: just as fast; now ports to Windows
* GxB_BURBLE added: for diagnostic output
* (21) bug fix: A({lo,hi})=scalar in MATLAB; A(lo:hi)=scalar was OK