| 1 | #include <list> |
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| 2 | #include "elt.hpp" |
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| 3 | #include "polyg.hpp" |
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| 4 | |
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| 5 | namespace sphereRemap { |
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| 6 | |
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| 7 | using namespace std; |
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| 8 | |
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| 9 | void cptEltGeom(Elt& elt, const Coord &pole) |
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| 10 | { |
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| 11 | orient(elt.n, elt.vertex, elt.edge, elt.d, elt.x); |
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| 12 | normals(elt, pole); |
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| 13 | Coord gg; |
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| 14 | elt.area = airbar(elt.n, elt.vertex, elt.edge, elt.d, pole, gg); |
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| 15 | elt.x = gg; |
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| 16 | } |
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| 17 | |
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| 18 | void cptAllEltsGeom(Elt *elt, int N, const Coord &pole) |
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| 19 | { |
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| 20 | for (int ne=0; ne<N; ne++) |
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| 21 | cptEltGeom(elt[ne], pole); |
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| 22 | } |
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| 23 | |
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| 24 | /* for all elements of size-N-array `elt`, |
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| 25 | make centre areaweighted average centres of super mesh elements */ |
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| 26 | void update_baryc(Elt *elt, int N) |
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| 27 | { |
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| 28 | for (int ne=0; ne<N; ne++) |
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| 29 | { |
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| 30 | Elt &e = elt[ne]; |
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| 31 | int ns = e.is.size(); // sous-elements |
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| 32 | Coord *sx = new Coord[ns]; |
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| 33 | int i=0; |
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| 34 | for (list<Polyg*>::iterator it = e.is.begin(); it != e.is.end(); i++, it++) |
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| 35 | { |
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| 36 | sx[i] = (*it)->x * (*it)->area; |
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| 37 | } |
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| 38 | e.x = barycentre(sx, ns); |
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| 39 | } |
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| 40 | } |
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| 41 | |
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| 42 | Coord gradient(Elt& elt, Elt **neighElts) |
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| 43 | { |
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| 44 | Coord grad = ORIGIN; |
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| 45 | Coord *neighBaryc = new Coord[elt.n]; |
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| 46 | for (int j = 0; j < elt.n; j++) |
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| 47 | { |
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| 48 | int k = (j + 1) % elt.n; |
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| 49 | neighBaryc[j] = neighElts[j]->x; |
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| 50 | Coord edgeNormal = crossprod(neighElts[k]->x, neighElts[j]->x); |
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| 51 | |
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| 52 | /* use nomenclauture form paper */ |
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| 53 | double f_i = elt.val; |
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| 54 | double f_j = neighElts[j]->val; |
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| 55 | double f_k = neighElts[k]->val; |
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| 56 | grad = grad + edgeNormal * (0.5*(f_j + f_k) - f_i); |
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| 57 | } |
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| 58 | /* area of the polygon whoes vertices are the barycentres the neighbours */ |
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| 59 | grad = grad * (1./polygonarea(neighBaryc, elt.n)); |
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| 60 | delete[] neighBaryc; |
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| 61 | |
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| 62 | return grad - elt.x * scalarprod(elt.x, grad); |
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| 63 | } |
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| 64 | |
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| 65 | void computeGradients(Elt **elts, int N) |
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| 66 | { |
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| 67 | |
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| 68 | for (int j = 0; j < N; j++) |
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| 69 | elts[j]->val = 0; |
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| 70 | |
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| 71 | Elt *neighbours[NMAX]; |
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| 72 | for (int j = 0; j < N; j++) |
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| 73 | { |
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| 74 | for (int i = 0; i < elts[j]->n; i++) |
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| 75 | neighbours[i] = elts[elts[j]->neighbour[i]]; |
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| 76 | |
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| 77 | for (int i = 0; i < elts[j]->n; i++) |
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| 78 | neighbours[i]->val = 0; |
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| 79 | for (int i = 0; i < elts[j]->n; i++) |
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| 80 | { |
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| 81 | elts[j]->neighId[i] = neighbours[i]->src_id; |
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| 82 | /* for weight computation all values are always kept zero and only set to one when used .. */ |
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| 83 | neighbours[i]->val = 1; |
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| 84 | elts[j]->gradNeigh[i] = gradient(*(elts[j]), neighbours); |
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| 85 | /* .. and right after zeroed again */ |
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| 86 | neighbours[i]->val = 0; |
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| 87 | } |
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| 88 | elts[j]->neighId[elts[j]->n].rank = -1; // mark end |
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| 89 | elts[j]->neighId[elts[j]->n].ind = -1; // mark end |
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| 90 | /* For the most naive algorithm the case where the element itself is one must also be considered. |
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| 91 | Thomas says this can later be optimized out. */ |
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| 92 | elts[j]->val = 1; |
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| 93 | elts[j]->grad = gradient(*(elts[j]), neighbours); |
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| 94 | elts[j]->val = 0; |
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| 95 | } |
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| 96 | } |
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| 97 | |
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| 98 | } |
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