Edge Reduction for EVMDDs to Speed Up Analysis of Multi-state Systems

This paper introduces a reduction rule for edge-valued multi-valued decision diagrams (EVMDDs), which improves the speed of analysis of multi-state systems (MSSs). Most reduction rules for decision diagrams remove redundant nodes, while the introduced rule removes redundant edges in EVMDDs. Since the time to do an analysis in an MSS depends on the number of edges in the EVMDD, the introduced rule makes analysis of MSSs faster, especially when used with hedge minimization algorithms based on variable grouping. Experimental results show that the introduced rule reduces the number of edges by up to 30%, and this results in an analysis time that is reduced by up to 30%.