Changelog. A lot less detailed than usual, at least for past
	history.
2022/05/20: Restart ChangeLog. Updated to new name AMG4PSBLAS, now using PSB3.8	
2018/10/28: Fix interface to MUMPS and configry machinery. Require PSB 3.6.
2018/10/10: ICTXT argument in prec%init().	
2018/07/30: Fixes for Intel compilers. BootCMatch interface in examples. 	
2018/05/14: Interface for extension of aggregation methods. 	
2018/02/28: New cartesian distribution for sample programs.	
2017/12/15: New WRK component of preconditioner levels, preallocation.	
2017/10/25: New example input file formats. Added sample matrices.	
2017/10/02: New CBIND in PSBLAS 3.5.0	
2017/07/30: Refactored examples. Change default thresholds. 
2017/05/31: New internal description of ML. 
2017/05/16: Improve build process. 
2017/04/20: Force %set interface. Update docs.	
2017/04/03: Remove obsolete stuff. 	
2017/03/17: Fixed level%cnv;  add coarse _solver tracker.	
2017/02/18: Take out clean_zeros; changed NOFILTER; defined FBGS; take out
	n_prec_levs.
2017/02/12: Updated mat_dist usage, dubious SP shell for UMFPACK, fixes
	for RPM packaging.      
2017/02/02: Fix superlu configury	
2016/11/12: Fix hierarchy/smoothers build to handle 1 level.	
2016/10/03: Merged changes to hierearchy building.	
2016/08/20: Reimplemented decoupled aggregation	
2016/07/20: Refactored application of multilevel. Defined V,W and
	K-cycles. 	
2016/05/18: Reworked internals of PRECSET. Defined  Forward-Backward
	Gauss-Seidel solver. Now available separate PRE and POST smoother
	objects. 
2016/03/30: MUMPS interface.	
2016/02/28: Hybrid Gauss-Seidel method. 	
2016/02/03: unify integer argument checks.	
2015/12/15: defaults single vs. double precision. Use clean_zeros.	
2015/12/08: new matdist interface	
2015/10/17: configry fixes	
2015/10/13: Fixes for SLUDIST versions 3 and 4
2015/05/03: New heap interface	
2015/04/21: INTENT fixes
	
2014/12/21: New error handling
	
2014/10/27: Added versioncheck to configure.
	
2014/03/31: New get_diag. 
	 
2013/11/07: Merged changes from experimental branch. Fix INCDIR in
	    makefiles. 
       
2013/07/15: Fixes for UMFPACK 5.4, SuperLU 4.3, SuperLU_Dist 3.3
	
2013/04/05: CLONE method.	
	
2013/03/08: Reworked SET routines. 	
	
2012/12/10: Enable long_integers.
	
2012/12/05: Split smoother/solver objects.	
	
2012/04/30: New scheme to find dynamically the number of level based on
	    the size of the coarse matrix
	
2012/01/10: Done split interface/implementation, plus subdir restructure.
	
2011/12/13: Start split interface/implementation to improve build time. 	
	
2011/11/25: Now works with _vect methods from PSBLAS. 	
	
2011/10/24: New test generation methods.
	
2011/06/15: Dump prolongator/restrictor
	
2011/04/14: Added MOLD argument(s) to precbld.       
	
2011/03/30: Fixed: descriptive methods, example programs.
	
2011/03/08: Re-factored modules for ILU methods.	
	
2011/03/04: Make X intent(inout) in APPLY to allow for preconditioners
            using SPMM. 	
	
2011/03/02: New set methods.
	
2011/01/07: Fixed UMF interfacing for Z data.

2011/01/04: Added UMF inteface for D data.
	
2011/01/02: Fix usage of DESC_DATA. Switched all names to F90 ending. 

2010/12/16: Fix usage of replicated space descriptor.

2010/11/16: Fix Jacobi smoother in case of empty off-diagonal. 	

2010/11/04: Defined and tested single real and complex.

2010/11/02: Aligned usage of sparse data type with psblas3.

2009/12/22: Aligned constants with mld2p4 v1.2

2009/12/11: First working version of double multilevel.

2009/12/05: Inttroduction of Smoother/Solver object hierarchy.

2009/09/23: Initial F2003 version. 	
      
	
2009/01/28: Changed names from XbaseprcY to XbaseprecY.
2009/01/27: Changed names from mld_transfer to mld_move_alloc.
	
2009/01/13: Repackaged the one-level preconditioners. Reorganized the
            build routines, taking out mlprec_bld, and switching the
	    number of levels when needed. 
2008/10/27: Changed the definition of prec_type: repackaged with a
	    onelev-prec-type, containing a baseprec and maps between
	    index spaces. No performance impact; no changes to
	    user-level interfaces.
	
2008/09/18: Changed mld_sizeof to integer(8); updated samples.	
	
2008/08/26: Fixed matrix generation in sample programs. 
	
2008/07/25: missing implicit none in mld_prec_type.	
	
2008/07/23: added HTML documentation  
	
2008/06/13: Fixed aggregation for replicated index spaces.

2008/06/02: Threshold into decoupled aggregation algorithm.
	
2008/05/27: Single precision version.

2008/03/09: Introduced configure script. 
	
2008/02/08: Merged changes from intermesh branch: we now have an
	    inter_desc_type object. Cleaned up data allocation and
	    variable initialization in multilevel prec application.

2008/01/10: Merged various fixes for: prologues, unused variables,
	    interface details.	
2007/12/21: Merge version with prologues and internal docs.
	
2007/11/15: Created pargen example.	

2007/11/14: Fix INTENT(IN) on X vector in preconditioner routines.

2007/10/19: Merged in ILU(P,T). To be tested extensively.

2007/10/17: Merged ILU(K) into trunk.

2007/10/16: Fixed ILU(K), it now performs satisfactorily. Also updated
	    ILU(0) to be more legible. 
	
2007/10/11: First working version of ILU(K). Still slow, there should
	    be room for improvement. 
	
2007/10/09: Added benchmark code.

2007/10/09: Added MILU_N_. Beware: values for UMF_ etc. have been
	    shifted. 

2007/10/02: To do: decide whether to name MLD_KRYLOV_MOD or
	    PSB_KRYLOV_MOD. 

2007/10/01: Start of this changelog. MLD2P4 now has a different
	    structure, to enable a build not embedded in PSBLAS.