Mercurial > repos > public > sbplib

view +sbp/D2Variable.m @ 1037:2d7ba44340d0 feature/burgers1d

Find changesets by keywords (author, files, the commit message), revision number or hash, or revset expression.
Pass scheme specific parameters as cell array. This will enabale constructDiffOps to be more general. In addition, allow for schemes returning function handles as diffOps, which is currently how non-linear schemes such as Burgers1d are implemented.
author Vidar Stiernström <vidar.stiernstrom@it.uu.se>
date Fri, 18 Jan 2019 09:02:02 +0100
parents 52a9dedb9171
children 738de3a4058b
line wrap: on
line source

classdef D2Variable < sbp.OpSet
    properties
        D1 % SBP operator approximating first derivative
        H % Norm matrix
        HI % H^-1
        Q % Skew-symmetric matrix
        e_l % Left boundary operator
        e_r % Right boundary operator
        D2 % SBP operator for second derivative
        M % Norm matrix, second derivative
        d1_l % Left boundary first derivative
        d1_r % Right boundary first derivative
        m % Number of grid points.
        h % Step size
        x % grid
        borrowing % Struct with borrowing limits for different norm matrices
    end

    methods
        function obj = D2Variable(m,lim,order)

            x_l = lim{1};
            x_r = lim{2};
            L = x_r-x_l;
            obj.h = L/(m-1);
            obj.x = linspace(x_l,x_r,m)';

            switch order

                case 6

                    [obj.H, obj.HI, obj.D1, obj.D2, ...
                    ~, obj.e_l, obj.e_r, ~, ~, ~, ~, ~,...
                     obj.d1_l, obj.d1_r] = ...
                        sbp.implementations.d4_variable_6(m, obj.h);
                    obj.borrowing.M.d1 = 0.1878;
                    obj.borrowing.R.delta_D = 0.3696;
                    % Borrowing e^T*D1 - d1 from R

                case 4
                    [obj.H, obj.HI, obj.D1, obj.D2, obj.e_l,...
                        obj.e_r, obj.d1_l, obj.d1_r] = ...
                        sbp.implementations.d2_variable_4(m,obj.h);
                    obj.borrowing.M.d1 = 0.2505765857;

                    obj.borrowing.R.delta_D = 0.577587500088313;
                    % Borrowing e^T*D1 - d1 from R
                case 2
                    [obj.H, obj.HI, obj.D1, obj.D2, obj.e_l,...
                        obj.e_r, obj.d1_l, obj.d1_r] = ...
                        sbp.implementations.d2_variable_2(m,obj.h);
                    obj.borrowing.M.d1 = 0.3636363636; 
                    % Borrowing const taken from Virta 2014

                    obj.borrowing.R.delta_D = 1.000000538455350;
                    % Borrowing e^T*D1 - d1 from R
                    
                otherwise
                    error('Invalid operator order %d.',order);
            end
            obj.borrowing.H11 = obj.H(1,1)/obj.h; % First element in H/h,
            obj.m = m;
            obj.M = [];
        end
        function str = string(obj)
            str = [class(obj) '_' num2str(obj.order)];
        end
    end


end