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1 classdef Rk4SecondOrderNonlin < time.Timestepper
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2 properties
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3 F
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4 k
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5 t
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6 w
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7 m
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8
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9 D
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10 E
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11 S
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12
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13 n
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14 end
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15
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16
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17 methods
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18 function obj = Rk4SecondOrderNonlin(D, E, S, k, t0, v0, v0t)
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19
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20 if S == 0
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21 S = @(v,t)0;
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22 end
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23
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24 if E == 0
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25 E = @(v,t)0;
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26 end
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27
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28 obj.k = k;
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29 obj.t = t0;
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30 obj.w = [v0; v0t];
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31
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32 m = length(v0);
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33 function wt = F(w,t)
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34 v = w(1:m);
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35 vt = w(m+1:end);
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36
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37 % Def: w = [v; vt]
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38 wt(1:m,1) = vt;
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39 wt(m+1:2*m,1) = D(v)*v + E(v)*vt + S(v,t);
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40
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41 end
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42
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43 obj.F = @F;
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44 obj.D = D;
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45 obj.E = E;
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46 obj.S = S;
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47 obj.m = m;
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48 end
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49
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50 function [v,t] = getV(obj)
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51 v = obj.w(1:end/2);
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52 t = obj.t;
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53 end
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54
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55 function [vt,t] = getVt(obj)
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56 vt = obj.w(end/2+1:end);
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57 t = obj.t;
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58 end
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59
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60 function obj = step(obj)
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61 obj.w = time.rk4.rungekutta_4(obj.w, obj.t, obj.k, obj.F);
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62 obj.t = obj.t + obj.k;
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63 obj.n = obj.n + 1;
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64 end
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65 end
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66
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67
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68 methods (Static)
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69 function k = getTimeStep(lambda)
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70 k = rk4.get_rk4_time_step(lambda);
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71 end
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72 end
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73
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74 end |
