/// <summary>
/// Inverts a property map-based relation.
/// </summary>
/// <param name="a">graph adapter providing temporary list storage</param>
/// <param name="srcrel">source property map</param>
/// <param name="dstrel">destination property map for inverted relation</param>
/// <param name="nodes">nodes to be considered for the inversion</param>
public static void InvertRelation <T>(this IGraphAdapter <T> a,
IPropMap <T, T[]> srcrel, IPropMap <T, T[]> dstrel, IEnumerable <T> nodes)
{
a.CreateDefaultTempStorage(nodes);
srcrel.RequireAccess(EAccess.ReadOnly);
dstrel.RequireAccess(EAccess.WriteOnly);
foreach (T node in nodes)
{
foreach (T adj in srcrel[node])
{
a.TempList[adj].Add(node);
}
}
foreach (T node in nodes)
{
dstrel[node] = a.TempList[node].ToArray();
}
a.TempList.Clear(nodes);
}
