1 | #ifndef __ELT_H__ |
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2 | #define __ELT_H__ |
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3 | #include <list> |
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4 | #include "triple.hpp" |
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5 | |
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6 | #define NMAX 10 /**< maximum number of vertices for polygons */ |
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7 | |
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8 | #define NOT_FOUND -1 |
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9 | |
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10 | namespace sphereRemap { |
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11 | |
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12 | using namespace std; |
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13 | |
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14 | Coord barycentre(const Coord *x, int n); |
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15 | |
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16 | /** Two great or small circles (or mixed) have two or zero intersections. |
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17 | The coordinates of the intersections are stored in `pt` and `nb` holds the number of intersections (0 or 2). |
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18 | */ |
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19 | struct Ipt |
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20 | { |
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21 | int nb; |
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22 | Coord pt[2]; |
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23 | }; |
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24 | |
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25 | struct Sgm // edge |
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26 | { |
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27 | Coord n; // normal |
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28 | Coord xt[2]; // endpoints |
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29 | double d; // (see Elt) |
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30 | }; |
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31 | |
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32 | struct GloId |
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33 | { |
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34 | int rank; |
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35 | int ind; /* local id */ |
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36 | long globalId ; |
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37 | |
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38 | bool operator<(const GloId& other) const { |
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39 | return (rank == other.rank) ? (ind < other.ind) : (rank < other.rank); |
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40 | } |
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41 | }; |
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42 | |
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43 | struct Polyg |
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44 | { |
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45 | /* Note: for the target grid elements the id (rank and local id) depends on the order of the target grid elements as read from the nc-file whereas for source grid elements it depends on the SS-tree (i.e. super mesh distribution, not the order in the nc-file) */ |
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46 | struct GloId id; |
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47 | struct GloId src_id; |
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48 | int n; /* number of vertices */ |
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49 | double area; |
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50 | double given_area ; |
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51 | Coord x; /* barycentre */ |
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52 | }; |
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53 | |
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54 | struct Elt : Polyg |
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55 | { |
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56 | Elt() {} |
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57 | Elt(const double *bounds_lon, const double *bounds_lat, int max_num_vert) |
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58 | { |
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59 | int k = 0; |
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60 | vertex[k++] = xyz(bounds_lon[0], bounds_lat[0]); |
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61 | for (int i = 1; i < max_num_vert; i++) |
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62 | { |
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63 | vertex[k] = xyz(bounds_lon[i], bounds_lat[i]); |
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64 | /* netCDF convention: if first vertex repeats element is finished (at least three vertices == triagle) */ |
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65 | if (k >= 3 && squaredist(vertex[k], vertex[0]) < EPS*EPS) |
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66 | break; |
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67 | /* eliminate zero edges: move to next vertex only if it is different */ |
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68 | if (squaredist(vertex[k], vertex[k-1]) > EPS*EPS) |
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69 | k++; |
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70 | else |
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71 | /* cout << "Removed edge " << k << " due to zero length (coinciding endpoints)." << endl */ ; |
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72 | } |
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73 | n = k; |
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74 | x = barycentre(vertex, n); |
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75 | } |
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76 | |
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77 | Elt& operator=(const Elt& rhs) |
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78 | { |
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79 | id = rhs.id; |
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80 | src_id = rhs.src_id; |
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81 | n = rhs.n; |
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82 | area = rhs.area; |
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83 | given_area = rhs.given_area; |
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84 | x = rhs.x; |
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85 | val = rhs.val; |
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86 | grad = rhs.grad; |
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87 | is = rhs.is; |
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88 | |
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89 | for(int i = 0; i < NMAX; i++) |
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90 | { |
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91 | neighbour[i] = rhs.neighbour[i]; |
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92 | d[i] = rhs.d[i]; |
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93 | edge[i] = rhs.edge[i]; |
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94 | vertex[i] = rhs.vertex[i]; |
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95 | gradNeigh[i] = rhs.gradNeigh[i]; |
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96 | } |
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97 | return *this; |
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98 | } |
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99 | |
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100 | void delete_intersections() |
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101 | { |
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102 | for (list<Polyg*>::iterator it = this->is.begin(); it != this->is.end(); it++) |
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103 | { |
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104 | Polyg* poly = *it; |
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105 | delete poly; |
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106 | } |
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107 | } |
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108 | |
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109 | void insert_vertex(int i, const Coord& v) |
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110 | { |
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111 | for(int j=n; j > i ; j--) |
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112 | { |
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113 | vertex[j]=vertex[j-1] ; |
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114 | edge[j]=edge[j-1] ; |
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115 | d[j]=d[j-1] ; |
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116 | neighbour[j]=neighbour[j-1] ; |
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117 | } |
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118 | vertex[i+1]=v ; |
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119 | n++ ; |
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120 | } |
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121 | |
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122 | int neighbour[NMAX]; |
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123 | double d[NMAX]; /**< distance of centre of small circle to origin, zero if great circle */ |
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124 | double val; /**< value (sample if src element, interpolated if dest element) */ |
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125 | Coord vertex[NMAX]; |
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126 | Coord edge[NMAX]; /**< edge normals: if great circle tangential to sphere, if small circle parallel to pole */ |
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127 | Coord grad; /**< gradient of the reconstructed linear function over this element */ |
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128 | Coord gradNeigh[NMAX]; /**< for weight computation: gradients for val=1 at individual neighbours */ |
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129 | struct GloId neighId[NMAX]; /**< weight computation needs to know global IDs for all sources with "link" */ |
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130 | std::list<Polyg*> is; /**< intersections */ |
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131 | }; |
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132 | |
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133 | static double normals(Elt &elt, const Coord &pole) |
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134 | { |
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135 | double nmin = 17.; |
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136 | for (int i = 0; i < elt.n; i++) // supposed oriented |
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137 | { |
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138 | int j = (i+1) % elt.n; |
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139 | elt.edge[i] = crossprod(elt.vertex[j], elt.vertex[i]); |
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140 | Coord t = elt.vertex[j] - elt.vertex[i]; |
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141 | /* polygonal grid || vertices not on same latitude */ |
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142 | if (pole == ORIGIN || fabs(scalarprod(t, pole)) > EPS) // great circle |
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143 | { |
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144 | double n = norm(elt.edge[i]); |
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145 | //assert(n > 0); |
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146 | if (n < nmin) nmin = n; |
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147 | elt.edge[i] = proj(elt.edge[i]); |
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148 | elt.d[i] = 0.0; |
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149 | } |
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150 | else /* lan lot grid && vertices on same latitude => small circle */ |
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151 | { |
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152 | int north = (scalarprod(elt.edge[i], pole) < 0) ? -1 : 1; |
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153 | elt.edge[i] = pole * north; |
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154 | elt.d[i] = scalarprod(elt.vertex[i], elt.edge[i]); |
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155 | } |
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156 | } |
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157 | return nmin; |
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158 | } |
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159 | |
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160 | } |
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161 | |
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162 | #endif |
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