Aztec 2.1 Release Notes


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In addition to bug fixes, Aztec 2.1 has the following new features:

1) MPI communicators can now be used with Aztec.

2) Matrix-free interface is much improved.

   a) easier to provide matrices and preconditioners

b) an experimental getrow capability allows matrix-free codes use Aztec preconditioners.

3) A matrix-capture facility for exporting matrices to programs like matlab.

4) total solution time now appears in AZ_status

5) There are a number of experimental features that are not officially released (and so not discussed in the manual) such as solving complex arithmetic matrices, using pivoting within the bilu scheme, and using Aztec with multi-level preconditioners. Those interested in these should contact us.

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In order for Aztec 2.0 users to be compatible with Aztec2.1, several changes need to be made.

1) The only real makefile change is that MPI_LIB_DIR has been replaced by MPI_LIB in which the mpi library must be given (see the install README).

2) Calls to AZ_matvec_mult() should be replaced by either AZ_MSR_matvec_mult() or AZ_VBR_matvec_mult()

3) Calls to AZ_exchange_bdry(x, data_org) need to append proc_config to parameters:

     AZ_exchange_bdry(x, data_org, proc_config)

4) Calls to AZ_processor_info(proc_config) should be replaced by AZ_set_proc_config():

     MPI USERS    ==> AZ_set_proc_config( proc_config, MPI_COMM_WORLD); 

nonMPI USERS ==> AZ_set_proc_config( proc_config, AZ_NO_MPI);

5) For AZ_iterate() users, matrices have changed (see user's manual). In particular,

   a) The structure AZ_MATRIX should not be declared. Instead an AZ_MATRIX pointer is declared followed by 

         Amat = AZ_matrix_create(N_equations);
      where N_equations is the number of local matrix rows on this processor 

b) Fields in AZ_MATRIX should be set via

AZ_set_MSR(Amat, bindx, val, data_org, 0, NULL, AZ_LOCAL),

AZ_set_VBR(Amat, rpntr, cpntr, bpntr, indx, bindx, val, data_org, 0, NULL, AZ_LOCAL),

or

AZ_set_MATFREE(Amat, &pass_data, example_specific_matvec);

where '0, NULL, AZ_LOCAL' currently are not used but will allow for globally numbered matrices in the future, 'example_specific_matvec' is a user defined matvec function and 'pass_data' is a user defined void* data pointer passed back to the users 'matvec'.

c) AZ_matrix_destroy(&Amat) should be used for freeing.

NOTE: Does not free arrays passed in via set functions: bindx, val, data_org, rpntr, cpntr, bpntr, indx.

d) AZ_create_matrix(), AZ_create_commless_matrix(), AZ_delete_matrix(), and AZ_delete_commless_matrix() should no longer be used.

6) Preconditioners within the AZ_iterate() interface have changed. In particular,

   a) The structure AZ_PRECOND should not be declared. Instead an AZ_PRECOND pointer is declared followed by 
         Prec = AZ_precond_create(Pmat, precond_function, precond_data);
      where Pmat is an AZ_MATRIX*, precond_function is either AZ_precondition (to use Aztec preconditioners) 
      or a user-defined preconditioning function, and precond_data is a data pointer for use with a user's 
      preconditioner.
   b) AZ_precond_destroy(&Prec) should be used for freeing.

NOTE: Does not free Pmat or precond_data.


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