annotate +sbp/upwind4.m @ 105:1df4f3704b76 feature/arclen-param

Added error checking for all methods that use the derivative gp. Removed that from the to do list. Updated some comments.
author Martin Almquist <martin.almquist@it.uu.se>
date Mon, 07 Dec 2015 18:51:41 +0100
parents 4f5a65f49035
children
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47
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1 function [H, HI, Dp, Dm, e_1, e_m] = upwind4(m,h)
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2
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3 Hv=ones(m,1);
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4 Hv(1:4)=[49/144 61/48 41/48 149/144];
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5 Hv(m-3:m)=rot90(Hv(1:4),2);
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6 Hv = Hv*h;
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7 H = spdiag(Hv,0);
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8 HI = spdiag(1./Hv,0);
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10 q_diags = [-1, 0, 1, 2 3];
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11 q_stencil = [-1/4 -5/6 3/2 -1/2 1/12];
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12 Qp = stripeMatrix(q_stencil, q_diags,m);
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14 Q_U = [
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15 -0.1e1/0.48e2 0.205e3/0.288e3 -0.29e2/0.144e3 0.1e1/0.96e2;
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16 -0.169e3/0.288e3 -0.11e2/0.48e2 0.33e2/0.32e2 -0.43e2/0.144e3;
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17 0.11e2/0.144e3 -0.13e2/0.32e2 -0.29e2/0.48e2 0.389e3/0.288e3;
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18 0.1e1/0.32e2 -0.11e2/0.144e3 -0.65e2/0.288e3 -0.13e2/0.16e2;
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19 ];
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20
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21 Qp(1:4,1:4)=Q_U;
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22 Qp(m-3:m,m-3:m)=rot90(Q_U,2)'; %%% This is different from standard SBP
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23
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24 Qm=-Qp';
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25
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26 e_1=sparse(m,1);e_1(1)=1;
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27 e_m=sparse(m,1);e_m(m)=1;
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28
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29 Dp=HI*(Qp-1/2*e_1*e_1'+1/2*e_m*e_m') ;
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30
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31 Dm=HI*(Qm-1/2*e_1*e_1'+1/2*e_m*e_m') ;
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32 end