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annotate +util/tt2t.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 48b6fb693025
children
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1 % Converts a semidiscretized PDE from second order in time to first order in time.
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2 % v_tt = Dv + S
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3 % becomes
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4 % w_t = Mw + C
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5 % where
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6 % w = [ v ; v_t]
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7 % and
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8 % M = [0 I;
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9 % D 0];
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10 % C = [0;
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11 % S];
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12 function [M,C] = tt2t(D,S)
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13 default_arg('S',sparse(size(D)))
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14 time_dependent_bc = isa(S,'function_handle');
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15
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16 I = eye(size(D));
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17 O = zeros(size(D));
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18
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19 M = [O I;
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20 D O];
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21
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22 if ~time_dependent_bc
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23 C = [zeros(size(S)); S];
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24 else
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25 o = zeros(size(S(0)));
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26 C = @(t)([o; S(t)]);
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27 end
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28 end