Approximations by OBDDs and the Variable Ordering Problem
نویسندگان
چکیده
منابع مشابه
Equivalence Test and Ordering Transformation for Parity-OBDDs of Different Variable Ordering
Ordered binary decision diagrams (OBDDs) have already proved useful for example in the veriication of combinational and sequential circuits. But the applications are limited, since the decriptive power of OBDDs is limited. Therefore several more general BDD models are studied. In this paper the so{called Parity{OBDDs are considered. The two polynomial time algorithms given are motivated by the ...
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When genetic programming (GP) is used to find programs with Boolean inputs and outputs, ordered binary decision diagrams (OBDDs) are often used successfully. In all known OBDD-based GP-systems the variable ordering, a crucial factor for the size of OBDDs, is preset to an optimal ordering of the known test function. Certainly this cannot be done in practical applications, where the function to l...
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Abstract The size of Ordered Binary Decision Diagrams (OBDDs) is determined by the chosen variable ordering. A poor choice may cause an OBDD to be too large to fit into the available memory. The decision variant of the variable ordering problem is known to be NP -complete. We strengthen this result by showing that for each constant c > 1 there is no polynomial time approximation algorithm with ...
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When genetic programming (GP) is used to find programs with Boolean inputs and outputs, ordered binary decision diagrams (OBDDs) are often used successfully. In all known OBDD-based GP-systems the variable ordering, a crucial factor for the size of OBDDs, is preset to an optimal ordering of the known test function. Certainly this cannot be done in practical applications, where the function to l...
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An Ordered Binary Decision Diagram (OBDD) is a directed acyclic graph representing a Boolean function. The size of OBDDs largely depends on the variable ordering. In this paper, we show the size of the OBDD representing the i-th bit of the output of n-bit/n-bit integer division is (2 (n?i)=8) for any variable ordering. We also show that _-OBDDs, ^-OBDDs and-OBDDs representing integer division h...
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عنوان ژورنال:
- Electronic Colloquium on Computational Complexity (ECCC)
دوره 6 شماره
صفحات -
تاریخ انتشار 1999