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comparison +sbp/+implementations/d1_upwind_3.m @ 284:dae8c3a56f5e

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Merged in operator_remake (pull request #2) Operator remake
author Jonatan Werpers <jonatan.werpers@it.uu.se>
date Mon, 12 Sep 2016 12:53:02 +0200
parents f7ac3cd6eeaa
children 52b4cdf27633
comparison
equal deleted inserted replaced
282:18c023aaf3f7 284:dae8c3a56f5e
1 function [H, HI, Dp, Dm, e_1, e_m] = d1_upwind_3(m,h)
2
3 if(m<6)
4 error('Operator requires at least 6 grid points');
5 end
6
7 Hv = ones(m,1);
8 Hv(1:3) = [3/8; 7/6; 23/24];
9 Hv(m-2:m) = rot90(Hv(1:3),2);
10 Hv = Hv*h;
11 H = spdiag(Hv,0);
12 HI = spdiag(1./Hv,0);
13
14 q_diags = [-1, 0, 1, 2];
15 q_stencil = [-1/3 -1/2 1 -1/6];
16 Qp = stripeMatrix(q_stencil, q_diags,m);
17
18 Q_U = [
19 -1/24 17/24 -1/6;
20 -13/24 -1/4 23/24;
21 1/12 -11/24 -11/24;
22 ];
23 Qp(1:3,1:3)=Q_U;
24 Qp(m-2:m,m-2:m)=rot90(Q_U,2)'; %%% This is different from standard SBP
25
26 Qm=-Qp';
27
28 e_1=sparse(m,1);
29 e_1(1)=1;
30 e_m=sparse(m,1);
31 e_m(m)=1;
32
33 Dp=HI*(Qp-1/2*(e_1*e_1')+1/2*(e_m*e_m')) ;
34
35 Dm=HI*(Qm-1/2*(e_1*e_1')+1/2*(e_m*e_m')) ;
36 end
37