readme

这是Yousef Saad编写的矩阵运算的Fortran软件包（A basic tool-kit for sparse matrix computations (Version 2),包含常见的排序

		             ----------------- 
		             Current contents:
			     -----------------

 Solvers
 -------

 iters.f : This file currently has several basic iterative linear system
           solvers. They are:
           CG       -- Conjugate Gradient Method
           CGNR     -- Conjugate Gradient Method on Normal Residual equation
           BCG      -- Bi-Conjugate Gradient Method
           BCGSTAB  -- BCG stablized
           TFQMR    -- Transpose-Free Quasi-Minimum Residual method
           GMRES    -- Generalized Minimum RESidual method
           FGMRES   -- Flexible version of Generalized Minimum RESidual method
           DQGMRES  -- Direct verions of Quasi Generalized Minimum Residual 
                       method
           DBCG     -- BCG with partial pivoting

 Preconditioners
 ---------------
	
 ilut.f :  ILUT + GMRES: a combination of a robust preconditioner
	   using dual thresholding for dropping strategy and
	   the GMRES algorithm. ILU0 and MILU0 are also provided
	   for comparison purposes.
	   large number of updates on Feb 10, 1992 Y.S. 
	   ILUTP, or ILUT with partial pivoting is also provided.

 Drivers
 -------

 rilut.f : test program for GMRES/ILU*.
           It tests three preconditioners ilu0, milu0 and ilut using
           GMRES as the solver.

riters.f : test program for ITERS -- the basic iterative solvers
           with reverse communication.
           The test matrix is generated with GEN57PT.

riter2.f : test program for ITERS. It reads a Harwell/Boeing matrix
           from the standard input.

 Other
 -----

 itaux.f : The file contains some of the auxiliary functions that is
           required to run the test prgram rilut.f and riters.f It
           includes the routine that drive the reverse-communincation
           routines and the definitions of the partial differential
           equations used to generate the matrix in rilut.f and
	   riters.f.

 executables
 ----------- 

 rilut.ex : generated by "make rilut.ex" from the driver rilut.f
riters.ex : generated by "make riters.ex" from the driver riters.f
riter2.ex : generated by "make riter2.ex" from the driver riter2.f

	    see makefile for the details of the dependencies.