Changes in DDL/MPI
------------------

Tim Oliver
last updated: Aug95

For the future...
-----------------

Support for file I/O of permuted matrices.

Better support for non row-packed matrices!!!

More high level routines.

...plus lots more


Version 2.1.2 (Aug95)	
---------------------

*** NOT BACKWARDS COMPATIBLE WITH 2.1.1 ***

DDL_Sparse and DDL_Vector structures updated with header record and
DDL procedures changed accordingly to accept DDL_Prop. This required
considerable changes to many source files and has made this version
(and future versions) of the Library incompatible with user programs
and additional Library procedures written for version 2.1.1 or
before.

Added functions DDL_Objecttype and DDL_Tag to retrieve info from
DDL_Prop header.

Error handling updated. User error handler in C or FORTRAN possible.

Added function DDL_Gettime for timing programs using wall clock time
or elapsed time. Removed buggy gettime function.

Many bug fixes and minor improvements.

Added better comments in code.


Version 2.1.1 (Jun95)	
---------------------

Main change is the inclusion of a configure script.

Separated distribution into 2 tarfiles: ddl2.1.1.tar and
datasets.tar. When updating from one ddl version to another, only the
ddl tarfile is needed if the datasets tarfile has not changed. These
tarfiles are available compressed with compress or gzip.

DDL_Linsolve, used by tfqmrnc.f, put into separate file
user/linsolve.f and minor bug corrected.


Version 2.1 (Jun95)	
-------------------

Major user-level change is the addition of support for permutation
vectors for distributed sparse matrices. Matrices can now have a
logical row and column numbering which is different from the physical
numbering. DDL_Smv (matrix-vector multiply) and DDL_Trisolve
(Triangular solver) support permutations (for packed-row matrices
only). Note: file I/O still uses physical numbering (see demo programs
cmv.c and ctr.c for examples of use.)

The blocking parameter for physical distribution has been implemented. 

Linked list of object properties (DDL_Prop) added to distributed
object data structure. This is used to add permutation vectors,
communications structures and other optional structures to data
objects. 

Fixed to work with mpich-1.0.8. Both Fortran and C programs store C
MPI_Datatypes in objects.


Version 2 (Jan95)	
-----------------

First(!) MPI implementation. A complete rewrite in C of the original
FORTRAN version 2 DDL/PVM implementation.  With about same
functionality, but source much simpler and cleaner.  

Features: packed-row sparse; file I/O; sparse M-V; dense level-1 BLAS;
preconditioning; tfqmrnc iterative solver.

Platforms: running successfully on SPARCS under Solaris and SunOS 4;
on SGI multiprocessor; on IBM RS6000 workstation. MPI: ANL version.