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view +sbp/+implementations/d2_variable_hollow_2.m @ 1337:bf2554f1825d feature/D2_boundary_opt
Add periodic D1 and D2 operators for orders 8,10,12
author | Vidar Stiernström <vidar.stiernstrom@it.uu.se> |
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date | Fri, 13 May 2022 13:28:10 +0200 |
parents | b5907140c069 |
children |
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function [H, HI, D1, D2, e_l, e_r, d1_l, d1_r] = d2_variable_hollow_2(m,h) BP = 1; if(m<2*BP) error(['Operator requires at least ' num2str(2*BP) ' grid points']); end % Norm Hv = ones(m,1); Hv(1) = 1/2; Hv(m:m) = 1/2; Hv = h*Hv; H = spdiag(Hv, 0); HI = spdiag(1./Hv, 0); % Boundary operators e_l = sparse(m,1); e_l(1) = 1; e_r = rot90(e_l, 2); d1_l = sparse(m,1); d1_l(1:3) = 1/h*[-3/2 2 -1/2]; d1_r = -rot90(d1_l, 2); % D1 operator diags = -1:1; stencil = [-1/2 0 1/2]; D1 = stripeMatrix(stencil, diags, m); D1(1,1)=-1;D1(1,2)=1;D1(m,m-1)=-1;D1(m,m)=1; D1(m,m-1)=-1;D1(m,m)=1; D1=D1/h; %Q=H*D1 + 1/2*(e_1*e_1') - 1/2*(e_m*e_m'); nBP = 2; M = sparse(m,m); coeffs = load('sbplib/+sbp/+implementations/coeffs_d2_variable_2.mat'); function D2 = D2_fun(c) M_l = zeros(nBP, coeffs.nBPC); M_r = zeros(nBP, coeffs.nBPC); for i=1:coeffs.nBPC M_l = M_l + coeffs.C_l{i}*c(i); M_r = M_r + coeffs.C_r{i}*c(m-coeffs.nBPC+i); end M(1:nBP, 1:coeffs.nBPC) = M_l; M(m-nBP+1:m, m-coeffs.nBPC+1:m) = M_r; D2 = M/h^2; end D2 = @D2_fun; end