Guidelines for run/init/start

[Ben Strasser]

Please add a few guidelines to the documentation about what are the invariants, pre and post conditions guaranteed by all algorithm objects and about the intended usage pattern. This includes documenting whenever:

• The graph object and/or map objects must be fully constructed when the constructor of the algorithm object is run. (This is relevant if the graph and the algorithms objects are member of the same class, as may happen with algorithm objects that use a graph transformation based reduction.)

• At what point may the graph and the other algorithm parameters no longer be changed anymore without causing a crash or without invalidating the results. Calling start after changing the graph without rerunning init is allowed to crash. Changing the graph after start has completed should invalidate the results (or maybe not but in that case that behavior should be documented).

• Must the destructor of the algorithm object run before running the destructor of the graph object?