spider_fuse_vdata_quick_fix.py

def spider(g: BaseGraph[VT,ET], matches: List[MatchSpiderType[VT]]) -> RewriteOutputType[VT,ET]:
    '''Performs spider fusion given a list of matchings from ``match_spider(_parallel)``
    '''
    rem_verts: List[VT] = []
    etab: Dict[Tuple[VT,VT],List[int]] = dict()

    for m in matches:
        if g.row(m[0]) == 0:
            v0, v1 = m[1], m[0]
        else:
            v0, v1 = m[0], m[1]

        ground = g.is_ground(v0) or g.is_ground(v1)

        if ground:
            g.set_phase(v0, 0)
            g.set_ground(v0)
        elif g.type(v0) == VertexType.Z_BOX or g.type(v1) == VertexType.Z_BOX:
            if g.type(v0) == VertexType.Z:
                z_to_z_box(g, [v0])
            if g.type(v1) == VertexType.Z:
                z_to_z_box(g, [v1])
            g.set_phase(v0, 0)
            set_z_box_label(g, v0, get_z_box_label(g, v0) * get_z_box_label(g, v1))
        else:
            g.add_to_phase(v0, g.phase(v1))

        if g.track_phases:
            g.fuse_phases(v0,v1)

        # always delete the second vertex in the match
        rem_verts.append(v1)

        # MY ADDITION: add all new key/values from v1 to v0, however currently
        # if both have the same key, then just the one from v0 is preserved
        v0_vdata_keys = g.vdata_keys(v0)
        v1_vdata_keys = g.vdata_keys(v1)

        new_vdata_dict = {key: g.vdata(v0, key) for key in v0_vdata_keys}

        for key in v1_vdata_keys:
            if key in new_vdata_dict:
                # TODO: could raise special error
                # print("Error could be raised here")
                continue
            else:
                new_vdata_dict[key] = g.vdata(v1, key)

        for key, val in new_vdata_dict.items():
            g.set_vdata(v0, key, val)

        # edges from the second vertex are transferred to the first
        for e in g.incident_edges(v1):
            source, target = g.edge_st(e)
            if source != v1:
                other_vertex = source
            elif target != v1:
                other_vertex = target
            else: #self-loop
                other_vertex = v0
            new_e = (v0, other_vertex)
            if new_e not in etab: etab[new_e] = [0,0]
            etab[new_e][g.edge_type(e)-1] += 1
        etab[(v0,v0)][0] = 0 # remove simple edge loops
    return (etab, rem_verts, [], True)