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annotate +sbp/+implementations/d2_variable_periodic_6.m @ 1037:2d7ba44340d0 feature/burgers1d

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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 bbf303c1f0cf
children
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5ccf6aaf6d6b Add D2VariablePeriodic orders 4 and 6.
Martin Almquist <malmquist@stanford.edu>
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1 function [H, HI, D1, D2, e_l, e_r, d1_l, d1_r] = d2_variable_periodic_6(m,h)
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Martin Almquist <malmquist@stanford.edu>
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2 % m = number of unique grid points, i.e. h = L/m;
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3
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Martin Almquist <malmquist@stanford.edu>
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4 if(m<7)
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5 error(['Operator requires at least ' num2str(7) ' grid points']);
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6 end
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7
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Martin Almquist <malmquist@stanford.edu>
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8 % Norm
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Martin Almquist <malmquist@stanford.edu>
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9 Hv = ones(m,1);
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Martin Almquist <malmquist@stanford.edu>
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10 Hv = h*Hv;
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Martin Almquist <malmquist@stanford.edu>
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11 H = spdiag(Hv, 0);
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Martin Almquist <malmquist@stanford.edu>
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12 HI = spdiag(1./Hv, 0);
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13
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14
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Martin Almquist <malmquist@stanford.edu>
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15 % Dummy boundary operators
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Martin Almquist <malmquist@stanford.edu>
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16 e_l = sparse(m,1);
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Martin Almquist <malmquist@stanford.edu>
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17 e_r = rot90(e_l, 2);
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18
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Martin Almquist <malmquist@stanford.edu>
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19 d1_l = sparse(m,1);
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Martin Almquist <malmquist@stanford.edu>
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20 d1_r = -rot90(d1_l, 2);
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21
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22
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Martin Almquist <malmquist@stanford.edu>
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23 % D1 operator
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Martin Almquist <malmquist@stanford.edu>
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24 diags = -3:3;
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Martin Almquist <malmquist@stanford.edu>
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25 stencil = [-1/60 9/60 -45/60 0 45/60 -9/60 1/60];
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Martin Almquist <malmquist@stanford.edu>
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26 D1 = stripeMatrixPeriodic(stencil, diags, m);
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Martin Almquist <malmquist@stanford.edu>
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27 D1 = D1/h;
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28
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29 % D2 operator
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Martin Almquist <malmquist@stanford.edu>
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30 scheme_width = 7;
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Martin Almquist <malmquist@stanford.edu>
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31 scheme_radius = (scheme_width-1)/2;
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32
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Martin Almquist <malmquist@stanford.edu>
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33 r = 1:m;
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Martin Almquist <malmquist@stanford.edu>
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34 offset = scheme_width;
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Martin Almquist <malmquist@stanford.edu>
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35 r = r + offset;
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36
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37 function D2 = D2_fun(c)
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38 c = [c(end-scheme_width+1:end); c; c(1:scheme_width) ];
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39
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Martin Almquist <malmquist@stanford.edu>
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40 Mm3 = c(r-2)/0.40e2 + c(r-1)/0.40e2 - 0.11e2/0.360e3 * c(r-3) - 0.11e2/0.360e3 * c(r);
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Martin Almquist <malmquist@stanford.edu>
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41 Mm2 = c(r-3)/0.20e2 - 0.3e1/0.10e2 * c(r-1) + c(r+1)/0.20e2 + 0.7e1/0.40e2 * c(r) + 0.7e1/0.40e2 * c(r-2);
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Martin Almquist <malmquist@stanford.edu>
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42 Mm1 = -c(r-3)/0.40e2 - 0.3e1/0.10e2 * c(r-2) - 0.3e1/0.10e2 * c(r+1) - c(r+2)/0.40e2 - 0.17e2/0.40e2 * c(r) - 0.17e2/0.40e2 * c(r-1);
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Martin Almquist <malmquist@stanford.edu>
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43 M0 = c(r-3)/0.180e3 + c(r-2)/0.8e1 + 0.19e2/0.20e2 * c(r-1) + 0.19e2/0.20e2 * c(r+1) + c(r+2)/0.8e1 + c(r+3)/0.180e3 + 0.101e3/0.180e3 * c(r);
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44 Mp1 = -c(r-2)/0.40e2 - 0.3e1/0.10e2 * c(r-1) - 0.3e1/0.10e2 * c(r+2) - c(r+3)/0.40e2 - 0.17e2/0.40e2 * c(r) - 0.17e2/0.40e2 * c(r+1);
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45 Mp2 = c(r-1)/0.20e2 - 0.3e1/0.10e2 * c(r+1) + c(r+3)/0.20e2 + 0.7e1/0.40e2 * c(r) + 0.7e1/0.40e2 * c(r+2);
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46 Mp3 = c(r+1)/0.40e2 + c(r+2)/0.40e2 - 0.11e2/0.360e3 * c(r) - 0.11e2/0.360e3 * c(r+3);
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47
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Martin Almquist <malmquist@stanford.edu>
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48 vals = [Mm3,Mm2,Mm1,M0,Mp1,Mp2,Mp3];
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Martin Almquist <malmquist@stanford.edu>
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49 diags = -scheme_radius : scheme_radius;
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Jonatan Werpers <jonatan@werpers.com>
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50 M = spdiagsPeriodic(vals,diags);
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51
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52 M=M/h;
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53 D2=HI*(-M );
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54 end
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55 D2 = @D2_fun;
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56
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57
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