質問編集履歴
2
タグ変更
test
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test
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1
コード、タグ変更
test
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test
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@@ -2,11 +2,7 @@
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2
2
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3
3
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4
4
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5
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-
調べてたり何度試したりしましたが、
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5
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+
調べてたり何度試したりしましたが、今のところ各u=0.0;となります。
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6
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-
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7
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が出ます。
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8
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-
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-
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6
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11
7
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8
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@@ -20,4 +16,100 @@
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16
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21
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u(0,t) = u(1,t) =0, t∈(0,T),
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22
18
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23
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-
u(x,0) = sinπx, x∈(0,
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19
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u(x,0) = sinπx, x∈(0,
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20
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21
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```public class ex{
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22
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23
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static public void main(String[] args){
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24
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25
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26
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27
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double a = 0.0; double b = 1.0;
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28
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29
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int M = 10;
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30
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31
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double dx = (b-a)/(double)M;
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32
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33
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double T = 1.0;
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34
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35
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double t = 0.0;
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36
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37
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double x = 0.0;
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38
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39
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double dt = 0.5*dx*dx;
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40
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41
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double err= 0.0;
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42
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43
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int N = (int)(T/dt);
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44
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45
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46
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47
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double ua = 0.0; double ub = 0.0;
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48
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49
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double []u = new double[M+1];
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50
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51
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double []v = new double[M+1];
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52
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53
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54
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55
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for(int j=0; j<M+1; j++){
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56
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57
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u[j]=Math.sin(Math.PI*x);
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58
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59
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}
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60
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61
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for (int k=0; k<N+1; k++){
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62
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63
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for (int j=0; j<M-1; j++){
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64
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65
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x = x + dx*((double)j);
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66
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67
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v[j+1] = u[j+1] + (u[j+2] - 2*u[j+1] + u[j])*100*0.005;
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68
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69
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t = t + dt;
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70
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71
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}
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72
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73
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u = v;
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74
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75
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for (int j=0; j<M+1; j++){
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76
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77
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if (k == 5*(int)(k/5)){
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78
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79
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System.out.println(" t = "+t+", u["+j+"]= "+u[j]);
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80
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81
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}
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82
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83
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84
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85
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if(err < Math.abs(u[j] - exact(t,x))){
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86
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87
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err= Math.abs(u[j] - exact(t,x));
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88
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89
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System.out.println(" Error = "+err);
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90
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91
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}
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92
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93
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}
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94
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95
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96
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97
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}
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98
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99
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}
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100
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101
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102
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103
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public static double exact(double t, double x){
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104
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105
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double exact;
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106
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107
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exact = Math.exp(-Math.PI*Math.PI*t)* Math.sin(Math.PI*x);
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108
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109
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return exact;
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110
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111
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}
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112
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113
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}
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114
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115
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```1).
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