SATURN CASSINI - Free
CASSINI is a Visual-Basic program developed to significantly reduce SATURN runtimes when SATURN is used within a Variable Demand Model such as a simple DIADEM model or a more complex, bespoke modelling system. See Section 7.4.1 of SATURN Manual for a general discussion of the problems of convergence between supply (i.e., assignment/SATURN) and trip matrix demand models and Section 7.4.5 for a description of the iterative “cobweb” loops between supply and demand models whose runtimes CASSINI seeks to “optimise”.
CASSINI enables the user to automatically adjust the convergence targets set for each run of SATURN to match the current level of convergence achieved for the supply-demand “cobweb” loops. Typically, a ‘relaxed’ set of convergence criteria would be set for the initial loops when supply-demand convergence is poor and the trip matrices are still highly uncertain but these would be subsequently tightened as the overall model convergence improves; in other words, reducing the ‘over-convergence’ within the supply model (i.e., SATURN).
For further details on CASSINI, consult the Section 15.54 of the SATURN Manual.