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annotate +time/Rungekutta.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 4e5e53d6336c
children
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846
c6fcee3fcf1b Add generalized RungeKutta and RungeKuttaRV class which extracts its coefficients from a butcher tableau, specified on the scheme.
Vidar Stiernström <vidar.stiernstrom@it.uu.se>
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1 classdef Rungekutta < time.Timestepper
c6fcee3fcf1b Add generalized RungeKutta and RungeKuttaRV class which extracts its coefficients from a butcher tableau, specified on the scheme.
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2 properties
c6fcee3fcf1b Add generalized RungeKutta and RungeKuttaRV class which extracts its coefficients from a butcher tableau, specified on the scheme.
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3 F % RHS of the ODE
c6fcee3fcf1b Add generalized RungeKutta and RungeKuttaRV class which extracts its coefficients from a butcher tableau, specified on the scheme.
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4 k % Time step
c6fcee3fcf1b Add generalized RungeKutta and RungeKuttaRV class which extracts its coefficients from a butcher tableau, specified on the scheme.
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5 t % Time point
c6fcee3fcf1b Add generalized RungeKutta and RungeKuttaRV class which extracts its coefficients from a butcher tableau, specified on the scheme.
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6 v % Solution vector
c6fcee3fcf1b Add generalized RungeKutta and RungeKuttaRV class which extracts its coefficients from a butcher tableau, specified on the scheme.
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7 n % Time level
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4e5e53d6336c Correct documentation of Rungekutta
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8 scheme % The scheme used for the time stepping, e.g rk4, rk6 etc.
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c6fcee3fcf1b Add generalized RungeKutta and RungeKuttaRV class which extracts its coefficients from a butcher tableau, specified on the scheme.
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9 end
c6fcee3fcf1b Add generalized RungeKutta and RungeKuttaRV class which extracts its coefficients from a butcher tableau, specified on the scheme.
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10
c6fcee3fcf1b Add generalized RungeKutta and RungeKuttaRV class which extracts its coefficients from a butcher tableau, specified on the scheme.
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11
c6fcee3fcf1b Add generalized RungeKutta and RungeKuttaRV class which extracts its coefficients from a butcher tableau, specified on the scheme.
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12 methods
c6fcee3fcf1b Add generalized RungeKutta and RungeKuttaRV class which extracts its coefficients from a butcher tableau, specified on the scheme.
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13 % Timesteps v_t = F(v,t), using RK with specfied order from t = t0 with
c6fcee3fcf1b Add generalized RungeKutta and RungeKuttaRV class which extracts its coefficients from a butcher tableau, specified on the scheme.
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14 % timestep k and initial conditions v = v0
c6fcee3fcf1b Add generalized RungeKutta and RungeKuttaRV class which extracts its coefficients from a butcher tableau, specified on the scheme.
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15 function obj = Rungekutta(F, k, t0, v0, order)
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1c6f1595bb94 Clean up in RK time stepper schemes
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16 default_arg('order',4);
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c6fcee3fcf1b Add generalized RungeKutta and RungeKuttaRV class which extracts its coefficients from a butcher tableau, specified on the scheme.
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17 obj.F = F;
c6fcee3fcf1b Add generalized RungeKutta and RungeKuttaRV class which extracts its coefficients from a butcher tableau, specified on the scheme.
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18 obj.k = k;
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19 obj.t = t0;
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20 obj.v = v0;
c6fcee3fcf1b Add generalized RungeKutta and RungeKuttaRV class which extracts its coefficients from a butcher tableau, specified on the scheme.
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21 obj.n = 0;
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5b180c76578e Use the old implementation for RK4 until the different methods are profiled.
Vidar Stiernström <vidar.stiernstrom@it.uu.se>
parents: 847
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22 % TBD: Order 4 is also implemented in the butcher tableau, but the rungekutta_4.m implementation
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Vidar Stiernström <vidar.stiernstrom@it.uu.se>
parents: 847
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23 % might be slightly more efficient. Need to do some profiling before deciding whether or not to keep it.
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24 if (order == 4)
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25 obj.scheme = @time.rk.rungekutta_4;
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26 else
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27 % Extract the coefficients for the specified order
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parents: 847
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28 % used for the RK updates from the Butcher tableua.
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29 [s,a,b,c] = time.rk.butcherTableau(order);
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30 coeffs = struct('s',s,'a',a,'b',b,'c',c);
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31 obj.scheme = @(v,t,dt,F) time.rk.rungekutta(v, t , dt, F, coeffs);
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32 end
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c6fcee3fcf1b Add generalized RungeKutta and RungeKuttaRV class which extracts its coefficients from a butcher tableau, specified on the scheme.
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33 end
c6fcee3fcf1b Add generalized RungeKutta and RungeKuttaRV class which extracts its coefficients from a butcher tableau, specified on the scheme.
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34
c6fcee3fcf1b Add generalized RungeKutta and RungeKuttaRV class which extracts its coefficients from a butcher tableau, specified on the scheme.
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35 function [v,t] = getV(obj)
c6fcee3fcf1b Add generalized RungeKutta and RungeKuttaRV class which extracts its coefficients from a butcher tableau, specified on the scheme.
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36 v = obj.v;
c6fcee3fcf1b Add generalized RungeKutta and RungeKuttaRV class which extracts its coefficients from a butcher tableau, specified on the scheme.
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37 t = obj.t;
c6fcee3fcf1b Add generalized RungeKutta and RungeKuttaRV class which extracts its coefficients from a butcher tableau, specified on the scheme.
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38 end
c6fcee3fcf1b Add generalized RungeKutta and RungeKuttaRV class which extracts its coefficients from a butcher tableau, specified on the scheme.
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39
c6fcee3fcf1b Add generalized RungeKutta and RungeKuttaRV class which extracts its coefficients from a butcher tableau, specified on the scheme.
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40 function obj = step(obj)
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41 obj.v = obj.scheme(obj.v, obj.t, obj.k, obj.F);
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c6fcee3fcf1b Add generalized RungeKutta and RungeKuttaRV class which extracts its coefficients from a butcher tableau, specified on the scheme.
Vidar Stiernström <vidar.stiernstrom@it.uu.se>
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42 obj.t = obj.t + obj.k;
c6fcee3fcf1b Add generalized RungeKutta and RungeKuttaRV class which extracts its coefficients from a butcher tableau, specified on the scheme.
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43 obj.n = obj.n + 1;
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44 end
c6fcee3fcf1b Add generalized RungeKutta and RungeKuttaRV class which extracts its coefficients from a butcher tableau, specified on the scheme.
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45 end
c6fcee3fcf1b Add generalized RungeKutta and RungeKuttaRV class which extracts its coefficients from a butcher tableau, specified on the scheme.
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46 end