1 | ######################################################### |
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2 | # |
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3 | # Subdivide the GA domain. This module is primarily |
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4 | # responsible for building the ghost layer and |
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5 | # communication pattern |
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6 | # |
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7 | # |
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8 | # Author: Linda Stals, June 2005 |
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9 | # Modified: Linda Stals, Nov 2005 (optimise python code) |
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10 | # |
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11 | # |
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12 | ######################################################### |
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13 | |
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14 | import sys |
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15 | |
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16 | from Numeric import zeros, Float, Int, concatenate, \ |
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17 | reshape, arrayrange, take, nonzero |
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18 | |
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19 | from anuga.abstract_2d_finite_volumes.neighbour_mesh import Mesh |
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20 | |
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21 | |
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22 | |
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23 | ######################################################### |
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24 | # |
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25 | # Subdivide the triangles into non-overlapping domains. |
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26 | # |
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27 | # *) The subdivision is controlled by triangles_per_proc. |
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28 | # The first triangles_per_proc[0] triangles are assigned |
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29 | # to the first processor, the second triangles_per_proc[1] |
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30 | # are assigned to the second processor etc. |
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31 | # |
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32 | # *) nodes, triangles and boundary contains all of the |
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33 | # nodes, triangles and boundary tag information for the |
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34 | # whole domain. The triangles should be orientated in the |
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35 | # correct way and the nodes number consecutively from 0. |
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36 | # |
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37 | # ------------------------------------------------------- |
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38 | # |
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39 | # *) A dictionary containing the full_nodes, full_triangles |
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40 | # and full_boundary information for each processor is |
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41 | # returned. The node information consists of |
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42 | # [global_id, x_coord, y_coord]. |
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43 | # |
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44 | ######################################################### |
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45 | |
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46 | def submesh_full(nodes, triangles, boundary, triangles_per_proc): |
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47 | |
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48 | # Initialise |
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49 | |
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50 | tlower = 0 |
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51 | nproc = len(triangles_per_proc) |
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52 | nnodes = len(nodes) |
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53 | node_list = [] |
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54 | triangle_list = [] |
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55 | boundary_list = [] |
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56 | submesh = {} |
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57 | node_range = reshape(arrayrange(nnodes),(nnodes,1)) |
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58 | tsubnodes = concatenate((node_range, nodes), 1) |
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59 | |
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60 | # Loop over processors |
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61 | |
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62 | for p in range(nproc): |
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63 | |
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64 | # Find triangles on processor p |
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65 | |
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66 | tupper = triangles_per_proc[p]+tlower |
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67 | subtriangles = triangles[tlower:tupper] |
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68 | triangle_list.append(subtriangles) |
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69 | |
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70 | # Find the boundary edges on processor p |
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71 | |
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72 | subboundary = {} |
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73 | for k in boundary: |
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74 | if (k[0] >=tlower and k[0] < tupper): |
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75 | subboundary[k]=boundary[k] |
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76 | boundary_list.append(subboundary) |
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77 | |
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78 | # Find nodes in processor p |
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79 | |
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80 | nodemap = zeros(nnodes, 'i') |
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81 | for t in subtriangles: |
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82 | nodemap[t[0]]=1 |
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83 | nodemap[t[1]]=1 |
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84 | nodemap[t[2]]=1 |
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85 | |
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86 | node_list.append(take(tsubnodes,nonzero(nodemap))) |
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87 | |
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88 | # Move to the next processor |
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89 | |
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90 | tlower = tupper |
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91 | |
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92 | # Put the results in a dictionary |
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93 | |
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94 | submesh["full_nodes"] = node_list |
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95 | submesh["full_triangles"] = triangle_list |
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96 | submesh["full_boundary"] = boundary_list |
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97 | |
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98 | # Clean up before exiting |
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99 | |
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100 | del (nodemap) |
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101 | |
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102 | return submesh |
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103 | |
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104 | |
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105 | ######################################################### |
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106 | # |
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107 | # Build the ghost layer of triangles |
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108 | # |
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109 | # *) Given the triangle subpartion for the processor |
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110 | # build a ghost layer of triangles. The ghost layer |
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111 | # consists of two layers of neighbouring triangles. |
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112 | # |
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113 | # *) The vertices in the ghost triangles must also |
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114 | # be added to the node list for the current processor |
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115 | # |
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116 | # |
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117 | # ------------------------------------------------------- |
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118 | # |
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119 | # *) The extra triangles and nodes are returned. |
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120 | # |
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121 | # *) The node information consists of |
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122 | # [global_id, x_coord, y_coord]. |
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123 | # |
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124 | # *) The triangle information consists of |
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125 | # [triangle number, t], where t = [v1, v2, v3]. |
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126 | # |
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127 | ######################################################### |
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128 | |
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129 | def ghost_layer(submesh, mesh, p, tupper, tlower): |
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130 | |
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131 | ncoord = len(mesh.coordinates) |
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132 | ntriangles = len(mesh.triangles) |
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133 | |
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134 | # Find the first layer of boundary triangles |
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135 | |
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136 | trianglemap = zeros(ntriangles, 'i') |
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137 | for t in range(tlower, tupper): |
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138 | |
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139 | n = mesh.neighbours[t, 0] |
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140 | if n >= 0: |
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141 | if n < tlower or n >= tupper: |
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142 | trianglemap[n] = 1 |
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143 | n = mesh.neighbours[t, 1] |
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144 | if n >= 0: |
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145 | if n < tlower or n >= tupper: |
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146 | trianglemap[n] = 1 |
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147 | n = mesh.neighbours[t, 2] |
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148 | if n >= 0: |
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149 | if n < tlower or n >= tupper: |
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150 | trianglemap[n] = 1 |
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151 | |
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152 | # Find the second layer of boundary triangles |
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153 | |
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154 | for t in range(len(trianglemap)): |
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155 | if trianglemap[t]==1: |
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156 | n = mesh.neighbours[t, 0] |
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157 | if n >= 0: |
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158 | if (n < tlower or n >= tupper) and trianglemap[n] == 0: |
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159 | trianglemap[n] = 2 |
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160 | n = mesh.neighbours[t, 1] |
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161 | if n >= 0: |
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162 | if (n < tlower or n >= tupper) and trianglemap[n] == 0: |
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163 | trianglemap[n] = 2 |
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164 | n = mesh.neighbours[t, 2] |
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165 | if n >= 0: |
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166 | if (n < tlower or n >= tupper) and trianglemap[n] == 0: |
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167 | trianglemap[n] = 2 |
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168 | |
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169 | # Build the triangle list and make note of the vertices |
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170 | |
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171 | nodemap = zeros(ncoord, 'i') |
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172 | fullnodes = submesh["full_nodes"][p] |
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173 | |
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174 | subtriangles = [] |
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175 | for i in range(len(trianglemap)): |
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176 | if trianglemap[i] != 0: |
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177 | t = list(mesh.triangles[i]) |
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178 | nodemap[t[0]] = 1 |
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179 | nodemap[t[1]] = 1 |
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180 | nodemap[t[2]] = 1 |
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181 | |
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182 | trilist = reshape(arrayrange(ntriangles),(ntriangles,1)) |
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183 | tsubtriangles = concatenate((trilist, mesh.triangles), 1) |
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184 | subtriangles = take(tsubtriangles, nonzero(trianglemap)) |
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185 | |
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186 | # Keep a record of the triangle vertices, if they are not already there |
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187 | |
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188 | subnodes = [] |
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189 | for n in fullnodes: |
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190 | nodemap[int(n[0])] = 0 |
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191 | |
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192 | nodelist = reshape(arrayrange(ncoord),(ncoord,1)) |
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193 | tsubnodes = concatenate((nodelist, mesh.coordinates), 1) |
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194 | subnodes = take(tsubnodes, nonzero(nodemap)) |
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195 | |
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196 | # Clean up before exiting |
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197 | |
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198 | del (nodelist) |
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199 | del (trilist) |
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200 | del (tsubnodes) |
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201 | del (nodemap) |
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202 | del (trianglemap) |
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203 | |
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204 | # Return the triangles and vertices sitting on the boundary layer |
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205 | |
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206 | return subnodes, subtriangles |
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207 | |
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208 | ######################################################### |
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209 | # |
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210 | # Find the edges of the ghost trianlges that do not |
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211 | # have a neighbour in the current cell. These are |
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212 | # treated as a special type of boundary edge. |
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213 | # |
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214 | # *) Given the ghost triangles in a particular |
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215 | # triangle, use the mesh to find its neigbours. If |
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216 | # the neighbour is not in the processor set it to |
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217 | # be a boundary edge |
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218 | # |
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219 | # *) The vertices in the ghost triangles must also |
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220 | # be added to the node list for the current processor |
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221 | # |
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222 | # *) The boundary edges for the ghost triangles are |
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223 | # ignored. |
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224 | # |
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225 | # ------------------------------------------------------- |
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226 | # |
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227 | # *) The type assigned to the ghost boundary edges is 'ghost' |
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228 | # |
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229 | # *) The boundary information is returned as a directorier |
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230 | # with the key = (triangle id, edge no) and the values |
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231 | # assigned to the key is 'ghost' |
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232 | # |
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233 | # |
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234 | ######################################################### |
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235 | def is_in_processor(ghost_list, tlower, tupper, n): |
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236 | return (n in ghost_list) or (tlower <= n and tupper > n) |
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237 | |
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238 | def ghost_bnd_layer(ghosttri, tlower, tupper, mesh, p): |
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239 | |
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240 | ghost_list = [] |
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241 | subboundary = {} |
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242 | |
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243 | for t in ghosttri: |
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244 | ghost_list.append(t[0]) |
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245 | |
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246 | for t in ghosttri: |
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247 | n = mesh.neighbours[t[0], 0] |
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248 | if not is_in_processor(ghost_list, tlower, tupper, n): |
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249 | subboundary[t[0], 0] = 'ghost' |
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250 | |
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251 | n = mesh.neighbours[t[0], 1] |
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252 | if not is_in_processor(ghost_list, tlower, tupper, n): |
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253 | subboundary[t[0], 1] = 'ghost' |
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254 | |
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255 | n = mesh.neighbours[t[0], 2] |
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256 | if not is_in_processor(ghost_list, tlower, tupper, n): |
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257 | subboundary[t[0], 2] = 'ghost' |
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258 | |
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259 | return subboundary |
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260 | |
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261 | ######################################################### |
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262 | # |
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263 | # The ghost triangles on the current processor will need |
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264 | # to get updated information from the neighbouring |
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265 | # processor containing the corresponding full triangles. |
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266 | # |
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267 | # *) The tri_per_proc is used to determine which |
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268 | # processor contains the full node copy. |
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269 | # |
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270 | # ------------------------------------------------------- |
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271 | # |
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272 | # *) The ghost communication pattern consists of |
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273 | # [global node number, neighbour processor number]. |
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274 | # |
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275 | ######################################################### |
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276 | |
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277 | def ghost_commun_pattern(subtri, p, tri_per_proc): |
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278 | |
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279 | # Loop over the ghost triangles |
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280 | |
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281 | ghost_commun = zeros((len(subtri), 2), Int) |
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282 | |
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283 | for i in range(len(subtri)): |
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284 | global_no = subtri[i][0] |
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285 | |
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286 | # Find which processor contains the full triangle |
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287 | |
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288 | nproc = len(tri_per_proc) |
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289 | neigh = nproc-1 |
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290 | sum = 0 |
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291 | for q in range(nproc-1): |
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292 | if (global_no < sum+tri_per_proc[q]): |
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293 | neigh = q |
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294 | break |
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295 | sum = sum+tri_per_proc[q] |
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296 | |
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297 | # Keep a copy of the neighbour processor number |
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298 | |
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299 | ghost_commun[i] = [global_no, neigh] |
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300 | |
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301 | return ghost_commun |
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302 | |
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303 | ######################################################### |
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304 | # |
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305 | # The full triangles in this processor must communicate |
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306 | # updated information to neighbouring processor that |
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307 | # contain ghost triangles |
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308 | # |
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309 | # *) The ghost communication pattern for all of the |
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310 | # processor must be built before calling this processor. |
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311 | # |
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312 | # *) The full communication pattern is found by looping |
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313 | # through the ghost communication pattern for all of the |
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314 | # processors. Recall that this information is stored in |
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315 | # the form [global node number, neighbour processor number]. |
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316 | # The full communication for the neighbour processor is |
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317 | # then updated. |
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318 | # |
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319 | # ------------------------------------------------------- |
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320 | # |
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321 | # *) The full communication pattern consists of |
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322 | # [global id, [p1, p2, ...]], where p1, p2 etc contain |
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323 | # a ghost node copy of the triangle global id. |
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324 | # |
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325 | ######################################################### |
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326 | |
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327 | def full_commun_pattern(submesh, tri_per_proc): |
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328 | tlower = 0 |
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329 | nproc = len(tri_per_proc) |
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330 | full_commun = [] |
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331 | |
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332 | # Loop over the processor |
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333 | |
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334 | for p in range(nproc): |
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335 | |
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336 | # Loop over the full triangles in the current processor |
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337 | # and build an empty dictionary |
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338 | |
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339 | fcommun = {} |
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340 | tupper = tri_per_proc[p]+tlower |
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341 | for i in range(tlower, tupper): |
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342 | fcommun[i] = [] |
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343 | full_commun.append(fcommun) |
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344 | tlower = tupper |
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345 | |
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346 | # Loop over the processor again |
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347 | |
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348 | for p in range(nproc): |
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349 | |
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350 | # Loop over the ghost triangles in the current processor, |
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351 | # find which processor contains the corresponding full copy |
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352 | # and note that the processor must send updates to this |
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353 | # processor |
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354 | |
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355 | for g in submesh["ghost_commun"][p]: |
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356 | neigh = g[1] |
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357 | full_commun[neigh][g[0]].append(p) |
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358 | |
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359 | return full_commun |
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360 | |
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361 | |
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362 | ######################################################### |
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363 | # |
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364 | # Given the non-overlapping grid partition, an extra layer |
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365 | # of triangles are included to help with the computations. |
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366 | # The triangles in this extra layer are not updated by |
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367 | # the processor, their updated values must be sent by the |
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368 | # processor containing the original, full, copy of the |
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369 | # triangle. The communication pattern that controls these |
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370 | # updates must also be built. |
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371 | # |
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372 | # *) Assumes that full triangles, nodes etc have already |
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373 | # been found and stored in submesh |
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374 | # |
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375 | # *) See the documentation for ghost_layer, |
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376 | # ghost_commun_pattern and full_commun_pattern |
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377 | # |
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378 | # ------------------------------------------------------- |
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379 | # |
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380 | # *) The additional information is added to the submesh |
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381 | # dictionary. See the documentation for ghost_layer, |
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382 | # ghost_commun_pattern and full_commun_pattern |
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383 | # |
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384 | # *) The ghost_triangles, ghost_nodes, ghost_boundary, |
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385 | # ghost_commun and full_commun is added to submesh |
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386 | ######################################################### |
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387 | |
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388 | def submesh_ghost(submesh, mesh, triangles_per_proc): |
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389 | |
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390 | nproc = len(triangles_per_proc) |
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391 | tlower = 0 |
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392 | ghost_triangles = [] |
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393 | ghost_nodes = [] |
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394 | ghost_commun = [] |
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395 | ghost_bnd = [] |
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396 | |
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397 | # Loop over the processors |
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398 | |
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399 | for p in range(nproc): |
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400 | |
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401 | # Find the full triangles in this processor |
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402 | |
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403 | tupper = triangles_per_proc[p]+tlower |
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404 | |
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405 | # Build the ghost boundary layer |
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406 | |
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407 | [subnodes, subtri] = \ |
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408 | ghost_layer(submesh, mesh, p, tupper, tlower) |
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409 | ghost_triangles.append(subtri) |
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410 | ghost_nodes.append(subnodes) |
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411 | |
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412 | # Find the boundary layer formed by the ghost triangles |
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413 | |
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414 | subbnd = ghost_bnd_layer(subtri, tlower, tupper, mesh, p) |
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415 | ghost_bnd.append(subbnd) |
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416 | |
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417 | # Build the communication pattern for the ghost nodes |
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418 | |
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419 | gcommun = \ |
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420 | ghost_commun_pattern(subtri, p, triangles_per_proc) |
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421 | ghost_commun.append(gcommun) |
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422 | |
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423 | # Move to the next processor |
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424 | |
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425 | tlower = tupper |
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426 | |
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427 | |
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428 | # Record the ghost layer and communication pattern |
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429 | |
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430 | submesh["ghost_nodes"] = ghost_nodes |
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431 | submesh["ghost_triangles"] = ghost_triangles |
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432 | submesh["ghost_commun"] = ghost_commun |
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433 | submesh["ghost_boundary"] = ghost_bnd |
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434 | |
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435 | # Build the communication pattern for the full triangles |
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436 | |
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437 | full_commun = full_commun_pattern(submesh, triangles_per_proc) |
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438 | submesh["full_commun"] = full_commun |
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439 | |
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440 | # Return the submesh |
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441 | |
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442 | return submesh |
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443 | |
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444 | |
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445 | ######################################################### |
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446 | # |
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447 | # Certain quantities may be assigned to the triangles, |
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448 | # these quantities must be subdivided in the same way |
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449 | # as the triangles |
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450 | # |
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451 | # *) The quantities are ordered in the same way as the |
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452 | # triangles |
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453 | # |
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454 | # ------------------------------------------------------- |
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455 | # |
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456 | # *) The quantites attached to the full triangles are |
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457 | # stored in full_quan |
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458 | # |
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459 | # *) The quantities attached to the ghost triangles are |
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460 | # stored in ghost_quan |
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461 | ######################################################### |
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462 | |
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463 | def submesh_quantities(submesh, quantities, triangles_per_proc): |
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464 | |
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465 | nproc = len(triangles_per_proc) |
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466 | |
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467 | lower = 0 |
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468 | |
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469 | # Build an empty dictionary to hold the quantites |
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470 | |
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471 | submesh["full_quan"] = {} |
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472 | submesh["ghost_quan"] = {} |
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473 | for k in quantities: |
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474 | submesh["full_quan"][k] = [] |
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475 | submesh["ghost_quan"][k] = [] |
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476 | |
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477 | # Loop trough the subdomains |
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478 | |
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479 | for p in range(nproc): |
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480 | upper = lower+triangles_per_proc[p] |
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481 | |
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482 | # Find the global ID of the ghost triangles |
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483 | |
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484 | global_id = [] |
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485 | M = len(submesh["ghost_triangles"][p]) |
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486 | for j in range(M): |
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487 | global_id.append(submesh["ghost_triangles"][p][j][0]) |
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488 | |
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489 | # Use the global ID to extract the quantites information from |
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490 | # the full domain |
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491 | |
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492 | for k in quantities: |
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493 | submesh["full_quan"][k].append(quantities[k][lower:upper]) |
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494 | submesh["ghost_quan"][k].append(zeros( (M,3) , Float)) |
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495 | for j in range(M): |
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496 | submesh["ghost_quan"][k][p][j] = \ |
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497 | quantities[k][global_id[j]] |
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498 | |
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499 | lower = upper |
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500 | |
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501 | return submesh |
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502 | |
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503 | ######################################################### |
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504 | # |
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505 | # Build the grid partition on the host. |
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506 | # |
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507 | # *) See the documentation for submesh_ghost and |
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508 | # submesh_full |
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509 | # |
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510 | # ------------------------------------------------------- |
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511 | # |
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512 | # *) A dictionary containing the full_triangles, |
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513 | # full_nodes, full_boundary, ghost_triangles, ghost_nodes, |
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514 | # ghost_boundary, ghost_commun and full_commun is returned. |
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515 | # |
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516 | ######################################################### |
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517 | |
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518 | def build_submesh(nodes, triangles, edges, quantities, |
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519 | triangles_per_proc): |
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520 | |
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521 | # Temporarily build the mesh to find the neighbouring |
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522 | # triangles |
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523 | |
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524 | mesh = Mesh(nodes, triangles) |
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525 | |
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526 | # Subdivide into non-overlapping partitions |
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527 | |
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528 | submeshf = submesh_full(nodes, triangles, edges, \ |
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529 | triangles_per_proc) |
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530 | |
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531 | # Add any extra ghost boundary layer information |
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532 | |
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533 | submeshg = submesh_ghost(submeshf, mesh, triangles_per_proc) |
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534 | |
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535 | # Order the quantities information to be the same as the triangle |
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536 | # information |
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537 | |
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538 | submesh = submesh_quantities(submeshg, quantities, \ |
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539 | triangles_per_proc) |
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540 | |
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541 | return submesh |
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542 | |
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