demo3_run.m

五点差分型多重网格方法：各种插值算子的比较）

%==============================================
%      MAIN SCRIPT OF MULTIGRID---Q1 FEM   
%==============================================
%  zhiyong2008 finish
%  用外推多重网格方法解-△u+u=f,(0,1)x(0,1).黎曼0边界条件
%  [e-mail]
%================================================================
function demo3_run

demo_globals
include_globals
include_flags
disp('*****Starting my Multigrid:Zhiyong 2008 work*****');

for nx1 = [ 8  ];
    ny1 =nx1;                    %
    coarse_level = 3;            % Set current maximum number of levels
    nu1 = 3; nu2 = 3;            % Set number of pre- and post-smoothings
    wt = 0.95;                   % Set smoother weighting
    rhs_flag = 1;                % Select right-hand side
    %------------------------------------------------------------------
    %smooth_flag = WEIGHTED_JACOBI;% Select smoother
     smooth_flag = GAUSS_SEIDEL;  
   % smooth_flag = RB_GAUSS_SEIDEL;
    %----------------------------------------------------------------
    restrict_flag = INJECTION; % Select restriction operator
   %  restrict_flag = FULL_WEIGHTING;
   % restrict_flag = HALF_WEIGHTING;
    
   % restrict_flag = ZHIJIE; %This is INJECTION designed in my work.
   % restrict_flag = IVER_FULL_LOCAL_EQUATION;
    %restrict_flag = IVER_SEMI_LOCAL_EQUATION;
    %restrict_flag = RES_LOCAL;
    %restrict_flag = RES_LOCAL_SECOND;
    %----------------------------------------------------------------
     interp_flag = LINEAR;          % Select interpolation operator
    % interp_flag = FULL_LOCAL_EQUATION;
    
    %interp_flag = SEMI_LOCAL_EQUATION;
    %interp_flag = EIGHT_POINTS;
    %interp_flag = ONE_DIM_LOCAL_EQUATION;
    %interp_flag = EAST_SOUTH_AVERAGE;
    %interp_flag = WEST_SOUTH_AVERAGE;
    %interp_flag = TEST_FIVEPOINT ;
    %---------------------------------------------------------------
    solver_flag = VMG_SOLVE;           % Select solver
    precon_flag = NONE;          % Select preconditioner
    cycle_flag = V_CYCLE;        % Select cycle flag
    coarsening_flag = 0;         % Select coarsening
    coarse_solver_flag = DIRECT_SOLVE; % Select coarse-grid solve 
    cycle_flag = V_CYCLE;        % Select MG cycle

    % Method parameter defaults

    rtol = 1e-16;           % Set stopping tolerance on weighted residual
    prtol = 1e-16;          % Set stopping tol. on weighted pseudo-resid.
    max_it = 12;                 % Set maximum number of iterations
    max_time = 0;                % Set maximum number of seconds
    max_mflop = 0;               % Set maximum number of mflops
    num_runs = 1;                % Set number of experiments to run

    % Linear System defaults

    generate_matrix = 1;         % Must generate the matrix initially
    generate_rhs = 1;        % Must generate the right-hand side initially
    matrix_type = [];            % Matrix properties initially unknown


    if (generate_matrix)
       [x,y,A1,N1,b] = get_matrix_fem(nx1,ny1);
       
       generate_matrix = 0;
       multigrid_setup;
    end
    
    x0 = zeros(N1,1);
    fprintf('------------------------------------------------------------------------------------\n');
    fprintf('level=%d×%d,,',nx1,ny1);
    
    utrue= cos(pi*x).*cos(pi*y); 
    demo3_vmg(A1,b,x0,utrue',rtol,prtol,max_it,max_time,max_mflop);
    
        
end