PK_ERROR_code_t       PK_EDGE_contains_vector
(
--- received arguments ---
PK_EDGE_t             edge,      --- the edge
PK_VECTOR_t           vector,    --- the position vector

--- returned arguments ---
PK_TOPOL_t     *const topol      --- topology coincident with vector if any
)


This function determines whether the given position vector coincides with
the given edge.


Specific Errors:
    PK_ERROR_missing_geom           edge has no geometry


If vector does not coincide with the edge then topol is returned as
PK_ENTITY_null.  This will occur either if vector does not coincide with the
edges curve or if it is beyond that portion of the curve occupied by the
edge.

If vector coincides with a vertex of the given edge then topol will
return that vertex.  vector is taken to coincide with a vertex if it is
within that vertex's precision of the vertex's point.

If vector coincides with the given edge but not at a vertex, then topol
returns edge.  vector is taken to coincide with an edge if it is within
that edge's precision of the edge's curve.