1 | #include "Python.h" |
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2 | #include "numpy/arrayobject.h" |
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3 | #include "math.h" |
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4 | #include <stdio.h> |
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5 | const double pi = 3.14159265358979; |
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6 | |
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7 | |
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8 | // Shared code snippets |
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9 | #include "util_ext.h" |
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10 | |
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11 | |
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12 | //Innermost flux function (using w=z+h) |
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13 | int _flux_function(double *q_left, double *q_right, |
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14 | double normals, double g, double epsilon, double h0, |
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15 | double *edgeflux, double *max_speed) { |
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16 | |
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17 | int i; |
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18 | double flux_left[2], flux_right[2]; |
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19 | double w_left, h_left, uh_left, z_left, u_left, soundspeed_left; |
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20 | double w_right, h_right, uh_right, z_right, u_right, soundspeed_right; |
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21 | double z, s_max, s_min, denom; |
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22 | |
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23 | //printf("h0 = %f \n",h0); |
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24 | w_left = q_left[0]; |
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25 | uh_left = q_left[1]*normals; |
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26 | h_left = q_left[2]; |
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27 | z_left = q_left[3]; |
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28 | u_left = q_left[4]*normals; |
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29 | |
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30 | w_right = q_right[0]; |
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31 | uh_right = q_right[1]*normals; |
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32 | h_right = q_right[2]; |
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33 | z_right = q_right[3]; |
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34 | u_right = q_right[4]*normals; |
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35 | |
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36 | z = (z_left+z_right)/2.0; |
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37 | |
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38 | soundspeed_left = sqrt(g*h_left); |
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39 | soundspeed_right = sqrt(g*h_right); |
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40 | |
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41 | s_max = max(u_left+soundspeed_left, u_right+soundspeed_right); |
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42 | if (s_max < 0.0) s_max = 0.0; |
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43 | |
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44 | s_min = min(u_left-soundspeed_left, u_right-soundspeed_right); |
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45 | if (s_min > 0.0) s_min = 0.0; |
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46 | |
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47 | |
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48 | // Flux formulas |
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49 | flux_left[0] = u_left*h_left; |
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50 | flux_left[1] = u_left*u_left*h_left + 0.5*g*h_left*h_left; |
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51 | |
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52 | flux_right[0] = u_right*h_right; |
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53 | flux_right[1] = u_right*u_right*h_right + 0.5*g*h_right*h_right; |
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54 | |
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55 | // Flux computation |
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56 | denom = s_max-s_min; |
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57 | if (denom < epsilon) { |
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58 | for (i=0; i<2; i++) edgeflux[i] = 0.0; |
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59 | *max_speed = 0.0; |
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60 | } else { |
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61 | edgeflux[0] = s_max*flux_left[0] - s_min*flux_right[0]; |
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62 | edgeflux[0] += s_max*s_min*(q_right[0]-q_left[0]); |
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63 | edgeflux[0] /= denom; |
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64 | edgeflux[1] = s_max*flux_left[1] - s_min*flux_right[1]; |
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65 | edgeflux[1] += s_max*s_min*(q_right[1]-q_left[1]); |
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66 | edgeflux[1] /= denom; |
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67 | edgeflux[1] *= normals; |
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68 | |
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69 | // Maximal wavespeed |
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70 | *max_speed = max(fabs(s_max), fabs(s_min)); |
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71 | } |
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72 | return 0; |
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73 | } |
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74 | |
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75 | |
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76 | |
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77 | |
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78 | // Computational function for flux computation |
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79 | double _compute_fluxes_ext( |
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80 | double cfl, |
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81 | double timestep, |
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82 | double epsilon, |
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83 | double g, |
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84 | double h0, |
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85 | long* neighbours, |
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86 | long* neighbour_vertices, |
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87 | double* normals, |
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88 | double* areas, |
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89 | double* stage_edge_values, |
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90 | double* xmom_edge_values, |
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91 | double* bed_edge_values, |
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92 | double* height_edge_values, |
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93 | double* velocity_edge_values, |
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94 | double* stage_boundary_values, |
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95 | double* xmom_boundary_values, |
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96 | double* bed_boundary_values, |
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97 | double* height_boundary_values, |
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98 | double* velocity_boundary_values, |
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99 | double* stage_explicit_update, |
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100 | double* xmom_explicit_update, |
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101 | int number_of_elements, |
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102 | double* max_speed_array) { |
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103 | |
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104 | double flux[2], ql[5], qr[5], edgeflux[2]; |
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105 | double max_speed, normal; |
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106 | int k, i, ki, n, m, nm=0; |
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107 | |
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108 | |
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109 | for (k=0; k<number_of_elements; k++) { |
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110 | flux[0] = 0.0; |
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111 | flux[1] = 0.0; |
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112 | |
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113 | for (i=0; i<2; i++) { |
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114 | ki = k*2+i; |
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115 | |
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116 | ql[0] = stage_edge_values[ki]; |
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117 | ql[1] = xmom_edge_values[ki]; |
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118 | ql[2] = bed_edge_values[ki]; |
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119 | ql[3] = height_edge_values[ki]; |
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120 | ql[4] = velocity_edge_values[ki]; |
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121 | |
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122 | n = neighbours[ki]; |
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123 | if (n<0) { |
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124 | m = -n-1; |
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125 | qr[0] = stage_boundary_values[m]; |
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126 | qr[1] = xmom_boundary_values[m]; |
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127 | qr[2] = bed_edge_values[m]; |
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128 | qr[3] = height_edge_values[m]; |
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129 | qr[4] = velocity_edge_values[m]; |
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130 | } else { |
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131 | m = neighbour_vertices[ki]; |
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132 | nm = n*2+m; |
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133 | qr[0] = stage_edge_values[nm]; |
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134 | qr[1] = xmom_edge_values[nm]; |
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135 | qr[2] = bed_edge_values[nm]; |
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136 | qr[3] = height_edge_values[nm]; |
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137 | qr[4] = velocity_edge_values[nm]; |
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138 | } |
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139 | |
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140 | normal = normals[ki]; |
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141 | _flux_function(ql, qr, normal, g, epsilon, h0, edgeflux, &max_speed); |
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142 | flux[0] -= edgeflux[0]; |
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143 | flux[1] -= edgeflux[1]; |
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144 | |
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145 | // Update timestep based on edge i and possibly neighbour n |
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146 | if (max_speed > epsilon) { |
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147 | // Original CFL calculation |
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148 | |
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149 | timestep = min(timestep, 0.5*cfl*areas[k]/max_speed); |
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150 | if (n>=0) { |
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151 | timestep = min(timestep, 0.5*cfl*areas[n]/max_speed); |
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152 | } |
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153 | } |
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154 | } // End edge i (and neighbour n) |
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155 | flux[0] /= areas[k]; |
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156 | stage_explicit_update[k] = flux[0]; |
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157 | flux[1] /= areas[k]; |
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158 | xmom_explicit_update[k] = flux[1]; |
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159 | |
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160 | //Keep track of maximal speeds |
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161 | max_speed_array[k]=max_speed; |
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162 | } |
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163 | return timestep; |
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164 | } |
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165 | |
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166 | //========================================================================= |
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167 | // Python Glue |
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168 | //========================================================================= |
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169 | PyObject *compute_fluxes_ext(PyObject *self, PyObject *args) { |
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170 | |
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171 | PyObject |
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172 | *domain, |
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173 | *stage, |
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174 | *xmom, |
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175 | *bed, |
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176 | *height, |
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177 | *velocity; |
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178 | |
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179 | PyArrayObject |
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180 | *neighbours, |
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181 | *neighbour_vertices, |
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182 | *normals, |
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183 | *areas, |
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184 | *stage_vertex_values, |
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185 | *xmom_vertex_values, |
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186 | *bed_vertex_values, |
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187 | *height_vertex_values, |
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188 | *velocity_vertex_values, |
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189 | *stage_boundary_values, |
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190 | *xmom_boundary_values, |
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191 | *bed_boundary_values, |
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192 | *height_boundary_values, |
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193 | *velocity_boundary_values, |
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194 | *stage_explicit_update, |
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195 | *xmom_explicit_update, |
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196 | *max_speed_array; |
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197 | |
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198 | double timestep, epsilon, g, h0, cfl; |
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199 | int number_of_elements; |
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200 | |
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201 | |
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202 | // Convert Python arguments to C |
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203 | if (!PyArg_ParseTuple(args, "dOOOOOO", |
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204 | ×tep, |
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205 | &domain, |
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206 | &stage, |
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207 | &xmom, |
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208 | &bed, |
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209 | &height, |
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210 | &velocity)) { |
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211 | PyErr_SetString(PyExc_RuntimeError, "comp_flux_ext.c: compute_fluxes_ext_short could not parse input"); |
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212 | return NULL; |
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213 | } |
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214 | |
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215 | |
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216 | epsilon = get_python_double(domain,"epsilon"); |
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217 | g = get_python_double(domain,"g"); |
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218 | h0 = get_python_double(domain,"h0"); |
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219 | cfl = get_python_double(domain,"cfl"); |
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220 | |
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221 | |
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222 | neighbours = get_consecutive_array(domain, "neighbours"); |
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223 | neighbour_vertices= get_consecutive_array(domain, "neighbour_vertices"); |
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224 | normals = get_consecutive_array(domain, "normals"); |
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225 | areas = get_consecutive_array(domain, "areas"); |
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226 | max_speed_array = get_consecutive_array(domain, "max_speed_array"); |
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227 | |
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228 | stage_vertex_values = get_consecutive_array(stage, "vertex_values"); |
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229 | xmom_vertex_values = get_consecutive_array(xmom, "vertex_values"); |
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230 | bed_vertex_values = get_consecutive_array(bed, "vertex_values"); |
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231 | height_vertex_values = get_consecutive_array(height, "vertex_values"); |
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232 | velocity_vertex_values = get_consecutive_array(velocity, "vertex_values"); |
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233 | |
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234 | stage_boundary_values = get_consecutive_array(stage, "boundary_values"); |
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235 | xmom_boundary_values = get_consecutive_array(xmom, "boundary_values"); |
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236 | bed_boundary_values = get_consecutive_array(bed, "boundary_values"); |
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237 | height_boundary_values = get_consecutive_array(height, "boundary_values"); |
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238 | velocity_boundary_values = get_consecutive_array(velocity, "boundary_values"); |
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239 | |
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240 | |
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241 | stage_explicit_update = get_consecutive_array(stage, "explicit_update"); |
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242 | xmom_explicit_update = get_consecutive_array(xmom, "explicit_update"); |
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243 | |
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244 | number_of_elements = stage_vertex_values -> dimensions[0]; |
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245 | |
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246 | // Call underlying flux computation routine and update |
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247 | // the explicit update arrays |
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248 | timestep = _compute_fluxes_ext( |
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249 | cfl, |
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250 | timestep, |
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251 | epsilon, |
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252 | g, |
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253 | h0, |
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254 | (long*) neighbours -> data, |
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255 | (long*) neighbour_vertices -> data, |
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256 | (double*) normals -> data, |
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257 | (double*) areas -> data, |
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258 | (double*) stage_vertex_values -> data, |
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259 | (double*) xmom_vertex_values -> data, |
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260 | (double*) bed_vertex_values -> data, |
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261 | (double*) height_vertex_values -> data, |
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262 | (double*) velocity_vertex_values -> data, |
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263 | (double*) stage_boundary_values -> data, |
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264 | (double*) xmom_boundary_values -> data, |
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265 | (double*) bed_boundary_values -> data, |
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266 | (double*) height_boundary_values -> data, |
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267 | (double*) velocity_boundary_values -> data, |
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268 | (double*) stage_explicit_update -> data, |
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269 | (double*) xmom_explicit_update -> data, |
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270 | number_of_elements, |
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271 | (double*) max_speed_array -> data); |
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272 | |
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273 | |
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274 | Py_DECREF(neighbours); |
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275 | Py_DECREF(neighbour_vertices); |
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276 | Py_DECREF(normals); |
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277 | Py_DECREF(areas); |
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278 | Py_DECREF(stage_vertex_values); |
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279 | Py_DECREF(xmom_vertex_values); |
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280 | Py_DECREF(bed_vertex_values); |
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281 | Py_DECREF(height_vertex_values); |
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282 | Py_DECREF(velocity_vertex_values); |
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283 | Py_DECREF(stage_boundary_values); |
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284 | Py_DECREF(xmom_boundary_values); |
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285 | Py_DECREF(bed_boundary_values); |
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286 | Py_DECREF(height_boundary_values); |
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287 | Py_DECREF(velocity_boundary_values); |
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288 | Py_DECREF(stage_explicit_update); |
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289 | Py_DECREF(xmom_explicit_update); |
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290 | Py_DECREF(max_speed_array); |
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291 | |
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292 | |
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293 | // Return updated flux timestep |
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294 | return Py_BuildValue("d", timestep); |
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295 | } |
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296 | |
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297 | |
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298 | |
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299 | //------------------------------- |
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300 | // Method table for python module |
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301 | //------------------------------- |
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302 | |
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303 | static struct PyMethodDef MethodTable[] = { |
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304 | {"compute_fluxes_ext", compute_fluxes_ext, METH_VARARGS, "Print out"}, |
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305 | {NULL, NULL} |
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306 | }; |
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307 | |
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308 | // Module initialisation |
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309 | void initsww_comp_flux_ext(void){ |
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310 | Py_InitModule("sww_comp_flux_ext", MethodTable); |
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311 | import_array(); |
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312 | } |
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