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annotate findZeros.m @ 1031:2ef20d00b386 feature/advectionRV

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For easier comparison, return both the first order and residual viscosity when evaluating the residual. Add the first order and residual viscosity to the state of the RungekuttaRV time steppers
author Vidar Stiernström <vidar.stiernstrom@it.uu.se>
date Thu, 17 Jan 2019 10:25:06 +0100
parents 8368beb0d1b3
children
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8368beb0d1b3 Added function to calculate multiple solutions to an equation.
Jonatan Werpers <jonatan@werpers.com>
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1 % findZeros looks for solutions to the equation f(x)==0 within
8368beb0d1b3 Added function to calculate multiple solutions to an equation.
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2 % the limits lim with a granularity of h.
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3 % Returns a sorted list of unique solutions.
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4 function z = findZeros(f, lim, h)
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5 n = ceil((lim(2)-lim(1))/h);
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6 z0 = linspace(lim(1), lim(2), n);
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7
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8 z = zeros(1,n);
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9
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10 for i = 1:n
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11 zt(i) = fzero(f, z0(i));
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12 end
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13
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14 zt = sort(zt);
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15
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16 z = [];
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17 for i = 1:n
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18 if zt(i) < lim(1) || zt(i) > lim(2)
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19 continue
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20 end
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21
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22 if ~isempty(z) && abs(z(end) - zt(i)) < 1e-6
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23 continue
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24 end
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25
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26 z = [z zt(i)];
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27 end
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28
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29 % z = unique(z);
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30 end