# HG changeset patch # User Jaroslav Hajek # Date 1271747006 -7200 # Node ID 74cb77f0a163f6d294b2a09069954b67ec25dd35 # Parent 3f973f6c841c44d9584b45dba8d6576b8477f580 update NEWS diff -r 3f973f6c841c -r 74cb77f0a163 ChangeLog --- a/ChangeLog Tue Apr 20 08:42:03 2010 +0200 +++ b/ChangeLog Tue Apr 20 09:03:26 2010 +0200 @@ -1,3 +1,7 @@ +2010-04-20 Jaroslav Hajek + + * NEWS: Update. + 2010-04-16 David Bateman * PROJECTS: Update for new sparse functionality. diff -r 3f973f6c841c -r 74cb77f0a163 NEWS --- a/NEWS Tue Apr 20 08:42:03 2010 +0200 +++ b/NEWS Tue Apr 20 09:03:26 2010 +0200 @@ -239,6 +239,26 @@ ** rem and mod are now built-in functions. They also handle integer types efficiently using integer arithmetic. + ** Sparse indexing and indexed assignment has been mostly rewritten. + Since Octave uses compressed column storage for sparse matrices, + major attention is devoted to operations manipulating whole columns. + Such operations are now significantly faster, as well as some other + important cases. + + Further, it is now possible to pre-allocate a sparse matrix and + subsequently fill it by assignments, provided they meet certain + conditions. For more information, consult the `spalloc' function, + which is no longer a mere dummy. Consequently, nzmax and nnz are no + longer always equal in Octave. Octave may also produce a matrix with + nnz < nzmax as a result of other operations, so you should + consistently use nnz unless you really want to use nzmax + (i.e. the space allocated for nonzero elements). + + Sparse concatenation is also affected, and concatenating sparse + matrices, especially larger collections, is now significantly more + efficient. This applies to both the [] operator and the + cat/vertcat/horzcat functions. + Summary of important user-visible changes for version 3.2: ---------------------------------------------------------