PETSc
NEW FEATURES and CHANGES in PETSc 2.0.17
General:
-
Added support for Windows NT/95 using the Microsoft Developers Studio
Visual C++. See the file 'Installation' for details.
-
Other new machines on which this release has been tested: Cray T3E,
SGI Origin See the file petsc/Installation for a complete list.
TS (Timestepping Solvers):
- Modified the pseudo-transient continuation updates:
- Changed the default update to dt = current_dt*previous_fnorm/current_fnorm.
-
Added the routine TSPseudoIncrementDtFromInitialDt() and the
corresponding option -ts_pseudo_increment_dt_from_initial_dt to
indicate use of the alternative update formula dt
= initial_dt*initial_fnorm/current_fnorm.
- Changed the calling sequence of TSRegister().
SNES (Nonlinear Solvers):
-
Added support for computing large, sparse Jacobians efficiently via
finite differences, see Section 5.6 (Finite Difference Jacobian
Approximations) of the users manual.
-
Added the routines SNESGetNumberLinearIterations() and
SNESSetConvergenceHistory(). See man pages for details.
-
Activated a counter of function evaluations, which is used in
convergence tests to terminate solver if the number of function
evaluations exceeds a given tolerance. Note: Users of matrix-free
Newton-Krylov methods may need to reset the default allowable maximum
(1000), via SNESSetTolerances() or -snes_max_func
<maxfunc>.
- Changed the calling sequence of SNESRegister().
SLES (Linear Solvers):
KSP (Krylov Subspace Methods):
- Changed the calling sequence of KSPRegister().
PC (Preconditioners):
- Changed the calling sequence of PCRegister().
- New Additive Schwarz variants (preconditioner type PCASM)
-
Added the routine PCASMSetType() (and the corresponding option
-pc_asm_type [basic,restrict,interpolate,none]) for setting the
variant of the additive Schwarz method. See the man page and users
manual for details.
-
Changed the default variant of PCASM from full restriction and
interpolation to full restriction only, since this version requires
less communication and for many problems converges faster than the
basic variant that uses full restriction and interpolation. Users
can still employ the basic ASM by calling
PCASMSetType(pc,PC_ASM_BASIC) or by using the option -pc_asm_type
basic.
-
Added an interface to the SPAI preconditioner implementation of
Steven Bernard; see src/contrib/spai. This has undergone little
testing and optimization; it is intended mainly for
"hackers".
MAT (Matrices):
-
Added the matrix option,
MatSetOption(mat,MAT_NEW_NONZERO_LOCATION_ERROR), that will cause an
error if a new nonzero is generated in a sparse matrix. (currently
implemented for AIJ and BAIJ matrices only). This is a useful flag
when using SAME_NONZERO_PATTERN in calling SLESSetOperators() to
ensure that the nonzero pattern truely does remain unchanged. For
examples, see the programs
petsc/src/snes/examples/tutorials/[ex5.c,ex5f.F].
-
Added the routine MatSetUnfactored(), intended primarily for use with
in-place ILU(0) factorization as a preconditioner for matrix-free
Krylov methods. See the manual page for details.
-
Added the routines MatConvertRegisterAll() and MatLoadRegisterAll()
to allow the restriction of the matrix routines linked into an
application code. This can decrease the size of your executable and
the time it takes to link your program. For details, see the manual
page and petsc/src/snes/examples/tutorials/ex5.c
-
Added the routine MatSetValuesBlocked(), for more efficient assembly
of block AIJ formatted matrices (MATSEQBAIJ and MATMPIBAIJ).
- Changed the calling sequence of MatReorderingRegister();
DA (Distributed Arrays):
-
Added additional arguments to DACreate1d(), DACreate2d(), and
DACreate3d() to allow the user to set the distribution of nodes on
each processor; set these arguments to PETSC_NULL for the standard
default distribution.
- Modified DAGetInfo() to return the type of periodicity.
VEC (Vectors):
-
Added the routine VecCreateGhost() to create vectors that have ghost
padding at the end of the local array. This is useful for gathering
remote values to perform local calculations that involve
off-processor ghost values. This is often appropriate for codes using
unstructured grids. See petsc/src/vec/examples/tutorials/ex9.c for
possible usage.
IS (Index Sets):
Draw (Graphics):
-
Application codes should not need to use #include "draw.h"
anymore from C/C++, since this file is now included automatically
when "petsc.h" or any other PETSc include file is included.
Viewers:
- VIEWER_DRAWX_WORLD, VIEWER_DRAWX_SELF, VIEWER_MATLAB_WORLD are now supported from Fortran.
-
Added VIEWER_DRAWX_(MPI_Comm comm) from C. Useful for rapid code
prototyping without having to declare a Viewer.
System Routines:
-
Since memory leaks and uninitialized memory can be serious problems
for large-scale application codes, we've added several new tools to
assist in their diagnosis. These tools are all work in conjunction
with the PETSc memory allocation (the default for codes that are
compiled in debug mode with BOPT=[g,g_c++,g_complex]).
-
Added the runtime option -trmalloc_log, which activates logging of
all calls to malloc via the new routines PetscTrLog() and
PetscTrLogDump().
-
Added the routine PetscGetResidentSetSize() to determine the total
memory used by a process (this is activated by -trmalloc_log); see
the man page for details.
-
Added the option -trmalloc_nan for tracking down allocated memory
that is used before it has been initialized. This option calls the
new routines PetscInitializeNans() and PetscInitializeLargeInts(). So
far these work on the Sun4 system.
Error Handling:
-
The error checking macros SETERRQ() and SETERRA() now have the
calling sequence SETERRQ(int ierr,int pierr,char *message); where
pierr is an additional integer error code passed to the error
handler. Currently you should just set pierr=1.
-
Also, SETERRQ() and SETERRA() now use the macro __FUNC__ to keep
track of routine names. Users need not worry about this in their
application codes, but can take advantage of this feature if desired
by setting this macro before each user-defined routine that may call
SETERRQ(), SETERRA(), CHKERRQ(), or CHKERRA(). __FUNC__ should be set
to a string containing the routine name. For example, #undef __FUNC__
#define __FUNC__ "MyRoutine1" int MyRoutine1() { /* code
here */ return 0; } See petsc/src/snes/examples/tutorials/ex3.c for
an example.
-
PETSc error handlers now take two additional arguments. Consult the
man page for PetscPushErrorHandler() for more information.
Event Logging:
- Changed PLogPrintSummary(MPI_Comm,FILE *) to PLogPrintSummary(MPI_Comm,char *).
- Now the option -log_summary takes [filename] as an optional argument.
Fortran Interface:
-
Added some limited support for direct use of Fortran90 pointers in
the routines Vec[Get,Restore]ArrayF90(), Mat[Get,Restore]ArrayF90(),
IS[Get,Restore]IndicesF90(), ISBlock[Get,Restore]IndicesF90(),
VecDuplicateVecsF90(), VecDestroyVecsF90(), DAGetGlobalIndicesF90().
See the man pages and the section 'Fortran90' in the users manal for
details. Unfortunately, these routines currently work only with the
NAG F90 compiler. We hope to support other compilers as well, but we
will need assistance from the vendors since the Fortran90/C interface
is not a defined standard.
-
Added the macro PetscDoubleExp(a,b) = a d b (machines where double
precision arithmetic is used) = a e b (machines where single
precision arithmetic is used, e.g., Crays) This macro is intended for
use only if you wish to maintain a Fortran code that is portable to
both the Cray T3d/T3e and other Unix machines.
-
For mixed Fortran/C users: added the makefile flag FCONF that may be
used in place of the flag CONF. For an example of usage, see
src/vec/examples/tutorials/makefile