What is MGLab?

    MGLab is a set of public domain Matlab functions that defines an 
    interactive environment for experimenting with multigrid algorithms.  The 
    package solves two-dimensional elliptic partial differential equations 
    using finite differences and includes several built-in problems (Poisson
    Helmholtz, discontinuous coefficient problems and non-self adjoint
    problems).  A number of parameters controlling the V-cycle can be set
    using a point and click mechanism.  The menu-based user interface also
    allows a choice of several Krylov subspace accelerators (PCG, GMRES(k),
    BiCG/STAB).  The package exploits Matlabs visualization and
    sparse matrix features and has been structured to be extensible.

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MGLab Files

    The Graphical User Interface
 
        MGLab.m
        show_params.m
        set_defaults.m
        run.m
        multigrid_setup.m
        menu_header.m
        menu_item.m
        version_info.m
        Contents.m
    
    Global Variables
    
        include_globals.m
        extract_globals.m
        include_flags.m
        include_figs.m
    
    Linear Systems
    
        get_matrix.m
        sp_laplace.m
        sp_cutsq2d.m
        sp_convdiff.m
        get_rhs.m
    
    Solvers
    
        solve.m
        converged.m
        vmg.m
        fmg.m
        pcg.m
        pcgs.m
        pbicgstab.m
        pgmres.m
        sor.m
        get_SOR_omega.m
    
    Preconditioners
    
        precondition.m
        precond_mg.m
    
    Results
    
        update_results.m
    
    Multigrid Routines: High Level
    
        mg_cycle.m
        vmg_cycle.m
        fmg_cycle.m
        wmg_cycle.m
        halfvmg_cycle.m
    
    Multigrid Routines: Middle Level
    
        smooth.m
        residual.m
        restrict.m
        coarse_grid_solve.m
        interpolate.m
        sp_prolong.m
    
    Multigrid Routines: Low Level
    
        coarsest.m
        max_level.m
    
    Demos
    
        demo_globals.m
        demo1.m
        demo1_run.m
        demo2.m
        demo2_run.m
        demo2_Vcycle.m 
        demo3.m
        demo3_run.m
        demo3_vmg.m
        sint.m
        sint2.m
   
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Documentation
 
    Thanks to Craig Douglas, a PostScript version of a short paper describing
    MGLab is available from mgnet.  The paper can be retrieved by anonymous
    ftp to
                ftp.cerfacs.fr
    or          casper.cs.yale.edu
    in the directory
                pub/mgnet/Conferences/CopperMtn95
    The name of the file is
                bordner_saied.ps.gz
 
    To run MGLab, simply start up Matlab (Version 4.0 or later) and type
    `MGLab'.  You may wish to include this directory in your Matlab path by
    typing `path (path,pwd)' while in your MGLab directory.

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Future Releases
 
    Comments about and suggestions for improvements of the code are welcome:
    we plan to have future versions of MGLab that incorporate enhancements and
    bug fixes.  To be put on a mailing list to be informed of new versions,
    send email to James Bordner (bordner@cs.uiuc.edu).

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Revision History
   
       10 June 1995 V1.00beta: Initial release
       20 June 1995 V1.0:      SOR solver added

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James Bordner (bordner@cs.uiuc.edu)
Faisal Saied (saied@cs.uiuc.edu)
University of Illinois at Urbana-Champaign
Department of Computer Science
20 June 1995