Patent ID: 7149663

Claim:
A method of ordering variables of a binary decision diagram representation of a hardware system, comprising acts of: arranging the variables of the binary decision diagram in a representation of a graph, corresponding to the hardware system, the graph having a top, nodes and leaves, the nodes being labeled with the variables of the binary decision diagram and the leaves being labeled with a set of functions, thereby to generate labels for the nodes and leaves, whereby the set of functions labeling the leaves reachable from one of the nodes corresponds to the set of functions that depend on the variables labeling the one of the nodes; traversing the representation of the graph from the top down to produce a list of labels in a selected order; and using the selected order of the list to determine a sifting order in which the variables are to be sifted to restructure the binary decision diagram representation of the hardware system prior to sifting the variables.