| 1 | cdef extern from "planarity/graph.h": |
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| 2 | # TODO: point out to Robert how much shit I was able to erase already |
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| 3 | ctypedef struct graphNode: |
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| 4 | int v |
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| 5 | int link[2] |
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| 6 | ctypedef graphNode * graphNodeP |
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| 7 | |
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| 8 | ctypedef struct BM_graph: |
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| 9 | graphNodeP G |
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| 10 | int N |
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| 11 | ctypedef BM_graph * graphP |
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| 12 | |
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| 13 | cdef int OK, EMBEDFLAGS_PLANAR, NONPLANAR, NOTOK |
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| 14 | |
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| 15 | cdef graphP gp_New() |
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| 16 | cdef void gp_Free(graphP *pGraph) |
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| 17 | cdef int gp_InitGraph(graphP theGraph, int N) |
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| 18 | cdef int gp_AddEdge(graphP theGraph, int u, int ulink, int v, int vlink) |
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| 19 | cdef int gp_Embed(graphP theGraph, int embedFlags) |
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| 20 | cdef int gp_SortVertices(graphP theGraph) |
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| 21 | |
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| 22 | def is_planar(g, set_pos=True, set_emb=True, circular=False): |
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| 23 | # create to and from mappings to relabel vertices to the set {0,...,n-1} |
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| 24 | listto = g.vertices() |
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| 25 | ffrom = {} |
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| 26 | for vvv in listto: |
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| 27 | ffrom[vvv] = listto.index(vvv) |
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| 28 | to = {} |
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| 29 | for i from 0 <= i < len(listto): |
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| 30 | to[i] = listto[i] |
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| 31 | g.relabel(ffrom) |
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| 32 | |
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| 33 | cdef graphP theGraph |
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| 34 | theGraph = gp_New() |
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| 35 | cdef int status |
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| 36 | status = gp_InitGraph(theGraph, g.order()) |
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| 37 | if status != OK: |
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| 38 | raise RuntimeError("status does not equal ok.") |
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| 39 | for u, v, _ in g.edge_iterator(): |
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| 40 | gp_AddEdge(theGraph, u, 0, v, 0) |
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| 41 | status = gp_Embed(theGraph, EMBEDFLAGS_PLANAR) |
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| 42 | gp_SortVertices(theGraph) |
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| 43 | |
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| 44 | # use to and from mappings to relabel vertices back from the set {0,...,n-1} |
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| 45 | g.relabel(to) |
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| 46 | |
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| 47 | if status == NOTOK: |
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| 48 | raise RuntimeError("not ok.") |
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| 49 | elif status == NONPLANAR: |
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| 50 | # TODO: Kuratowski subgraph isolator |
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| 51 | gp_Free(&theGraph) |
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| 52 | return False |
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| 53 | else: |
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| 54 | if not circular: |
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| 55 | if set_emb: |
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| 56 | # TODO: explain to self why the following line doesn't compile |
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| 57 | #cdef int i |
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| 58 | emb_dict = {} |
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| 59 | for i in range(theGraph.N): |
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| 60 | #for i from 0 <= i < theGraph.N: |
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| 61 | linked_list = [] |
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| 62 | j = theGraph.G[i].link[1] |
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| 63 | while j >= theGraph.N: |
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| 64 | linked_list.append(to[theGraph.G[j].v]) |
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| 65 | j = theGraph.G[j].link[1] |
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| 66 | emb_dict[to[i]] = linked_list |
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| 67 | g.__embedding__ = emb_dict |
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| 68 | if set_pos: |
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| 69 | schnyder(g,emb_dict) |
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| 70 | else: |
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| 71 | if set_emb: |
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| 72 | # Take counter-clockwise embedding if circular planar test |
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| 73 | # Also, pos must be set after removing extra vertex and edges |
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| 74 | # |
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| 75 | # TODO: explain to self why the following line doesn't compile |
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| 76 | #cdef int i |
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| 77 | emb_dict = {} |
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| 78 | for i in range(theGraph.N): |
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| 79 | #for i from 0 <= i < theGraph.N: |
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| 80 | linked_list = [] |
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| 81 | j = theGraph.G[i].link[0] |
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| 82 | while j >= theGraph.N: |
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| 83 | linked_list.append(to[theGraph.G[j].v]) |
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| 84 | j = theGraph.G[j].link[0] |
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| 85 | emb_dict[to[i]] = linked_list |
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| 86 | g.__embedding__ = emb_dict |
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| 87 | gp_Free(&theGraph) |
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| 88 | return True |
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| 89 | |
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| 90 | def schnyder(g, emb_dict, circular=False): |
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| 91 | # TODO |
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| 92 | pass |
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| 93 | |
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| 94 | |
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| 95 | |
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